build: respect environment options more (#1392)

* build: update m4/ax_pthread.m4 from serial 23 -> serial 31

Update ax_pthread.m4 to the latest version from the autoconf-archive
project.

Signed-off-by: Sam James <sam@gentoo.org>

* build: properly detect AR, CC, RANLIB

It's necessary to be able to override choice of AR/CC/RANLIB and other toolchain
variables/tools for cross-compilation, testing with other toolchains, and
to ensure the compiler chosen by the user is actually used for the build.

Previously, GNU_PREFIX was kind-of used for this but this isn't a standard
variable (at all) and it wasn't applied consistently anyway.

We now use the standard autoconf mechanisms for finding these tools.

(RANLIB is already covered by LT_INIT.)

Signed-off-by: Sam James <sam@gentoo.org>

* build: use $(MAKE)

This ensures that parallel make works correctly, as otherwise, a fresh
make job will be started without the jobserver fd, and hence
not know about its parent, forcing -j1.

* build: respect CPPFLAGS, LDFLAGS

- CPPFLAGS is for the C preprocessor (usually for setting defines)
- LDFLAGS should be placed before objects for certain flags to work
  (e.g. -Wl,--as-needed)

Signed-off-by: Sam James <sam@gentoo.org>

Co-authored-by: Luca Deri <lucaderi@users.noreply.github.com>

8 files changed, 188 insertions, 144 deletions

diff --git a/configure.ac b/configure.ac
index b71a2ddee..4e5ee5b1a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -13,8 +13,6 @@ AS_IF([test "${with_only_libndpi+set}" = set],[
   EXTRA_TARGETS=""
 ])
 
-GNU_PREFIX=""
-
 AC_ARG_WITH(sanitizer,     AS_HELP_STRING([--with-sanitizer], [Build with support for address, undefined and leak sanitizer]))
 AC_ARG_ENABLE(fuzztargets, AS_HELP_STRING([--enable-fuzztargets], [Enable fuzz targets]),[enable_fuzztargets=$enableval],[enable_fuzztargets=no])
 AS_IF([test "x$enable_fuzztargets" = "xyes"], [BUILD_FUZZTARGETS=1], [BUILD_FUZZTARGETS=0])
@@ -36,11 +34,14 @@ dnl>  AC_PROG_CC(clang gcc)
   AC_PROG_CXX(clang++ g++)
   AC_PROG_CC_STDC(clang gcc)
 else
-dnl>  AC_PROG_CC
-  AM_PROG_CC_C_O
+  AC_PROG_CC
   AC_PROG_CXX
   AC_PROG_CC_STDC
 fi
+
+dnl> Can't iuse AM_PROG_AR because not all of our Makefiles are automake (yet?)
+AC_CHECK_TOOL(AR, ar, [false])
+
 AC_LANG_WERROR
 
 NDPI_MAJOR=`echo "${PACKAGE_VERSION}" | cut -d . -f 1`
@@ -163,7 +164,7 @@ case "$host" in
         ;;
       esac
       CFLAGS="${CFLAGS}"
-      LDFLAGS="${LDFLAGS} -lws2_32"
+      LIBS="${LIBS} -lws2_32"
       BUILD_MINGW=1
       ;;
    *)
@@ -305,5 +306,4 @@ AC_SUBST(JSONC_CFLAGS)
 AC_SUBST(JSONC_LIBS)
 AC_SUBST(GCRYPT_ENABLED)
 AC_SUBST(PCRE_ENABLED)
-AC_SUBST(GNU_PREFIX)
 AC_OUTPUT
diff --git a/example/Makefile.in b/example/Makefile.in
index 11c30ad5c..bd4353997 100644
--- a/example/Makefile.in
+++ b/example/Makefile.in
@@ -1,11 +1,13 @@
+AR=@AR@
 CC=@CC@
 CXX=@CXX@
 BUILD_MINGW=@BUILD_MINGW@
 BUILD_MINGW_X64=@BUILD_MINGW_X64@
 SRCHOME=../src
 CFLAGS=-g -fPIC -DPIC -I$(SRCHOME)/include @PCAP_INC@ @CFLAGS@
+LDFLAGS=@LDFLAGS@
 LIBNDPI=$(SRCHOME)/lib/libndpi.a
-LDFLAGS=$(LIBNDPI) @PCAP_LIB@ @LIBS@ @ADDITIONAL_LIBS@ @LDFLAGS@
+LIBS=$(LIBNDPI) @PCAP_LIB@ @LIBS@ @ADDITIONAL_LIBS@
 HEADERS=intrusion_detection.h reader_util.h $(SRCHOME)/include/ndpi_api.h \
         $(SRCHOME)/include/ndpi_typedefs.h $(SRCHOME)/include/ndpi_protocol_ids.h
 OBJS=ndpiReader.o reader_util.o intrusion_detection.o
@@ -14,17 +16,17 @@ PREFIX?=@prefix@
 ifneq ($(BUILD_MINGW),)
 SUFFIX:=.exe
 CFLAGS+=-I@srcdir@/../windows/WpdPack/Include -I@srcdir@/../windows/WpdPack/Include/pcap
-LDFLAGS+=-Wl,-Bstatic -lpthread -Wl,-Bdynamic
+LIBS+=-Wl,-Bstatic -lpthread -Wl,-Bdynamic
 
 ifneq ($(BUILD_MINGW_X64),)
-LDFLAGS+=@srcdir@/../windows/WpdPack/Lib/x64/wpcap.lib
+LIBS+=@srcdir@/../windows/WpdPack/Lib/x64/wpcap.lib
 else
-LDFLAGS+=@srcdir@/../windows/WpdPack/Lib/wpcap.lib
+LIBS+=@srcdir@/../windows/WpdPack/Lib/wpcap.lib
 endif
 
 else
 
-LDFLAGS+=-lpthread
+LIBS+=-lpthread
 
 endif
 
@@ -34,16 +36,16 @@ EXECUTABLE_SOURCES := ndpiReader.c ndpiSimpleIntegration.c
 COMMON_SOURCES := $(filter-out $(EXECUTABLE_SOURCES),$(wildcard *.c ))
 
 libndpiReader.a: $(COMMON_SOURCES:%.c=%.o) $(LIBNDPI)
-	ar rsv libndpiReader.a $(COMMON_SOURCES:%.c=%.o)
+	$(AR) rsv libndpiReader.a $(COMMON_SOURCES:%.c=%.o)
 
 ndpiReader$(SUFFIX): libndpiReader.a $(LIBNDPI) ndpiReader.o
-	$(CC) $(CFLAGS) ndpiReader.o libndpiReader.a -o $@ $(LDFLAGS)
+	$(CC) $(CFLAGS) $(LDFLAGS) ndpiReader.o libndpiReader.a $(LIBS) -o $@
 
 ndpiSimpleIntegration$(SUFFIX): ndpiSimpleIntegration.o
-	$(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
+	$(CC) $(CFLAGS) $(LDFLAGS) $< $(LIBS) -o $@
 
 %.o: %.c $(HEADERS) Makefile
-	$(CC) $(CFLAGS) -c $< -o $@
+	$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@
 
 install: ndpiReader$(SUFFIX)
 	mkdir -p $(DESTDIR)$(PREFIX)/bin/
@@ -56,7 +58,7 @@ install: ndpiReader$(SUFFIX)
 	[ -f ndpiReader.dpdk ] && cp ndpiReader.dpdk $(DESTDIR)$(PREFIX)/bin/ || true
 
 dpdk:
-	make -f Makefile.dpdk
+	$(MAKE) -f Makefile.dpdk
 
 check:
 	 cppcheck --template='{file}:{line}:{severity}:{message}' --quiet --enable=all --force -I$(SRCHOME)/include *.c
diff --git a/m4/ax_pthread.m4 b/m4/ax_pthread.m4
index 4c4051ea3..76169dcb8 100644
--- a/m4/ax_pthread.m4
+++ b/m4/ax_pthread.m4
@@ -1,5 +1,5 @@
 # ===========================================================================
-#        http://www.gnu.org/software/autoconf-archive/ax_pthread.html
+#        https://www.gnu.org/software/autoconf-archive/ax_pthread.html
 # ===========================================================================
 #
 # SYNOPSIS
@@ -14,20 +14,24 @@
 #   flags that are needed. (The user can also force certain compiler
 #   flags/libs to be tested by setting these environment variables.)
 #
-#   Also sets PTHREAD_CC to any special C compiler that is needed for
-#   multi-threaded programs (defaults to the value of CC otherwise). (This
-#   is necessary on AIX to use the special cc_r compiler alias.)
+#   Also sets PTHREAD_CC and PTHREAD_CXX to any special C compiler that is
+#   needed for multi-threaded programs (defaults to the value of CC
+#   respectively CXX otherwise). (This is necessary on e.g. AIX to use the
+#   special cc_r/CC_r compiler alias.)
 #
 #   NOTE: You are assumed to not only compile your program with these flags,
 #   but also to link with them as well. For example, you might link with
 #   $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
+#   $PTHREAD_CXX $CXXFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
 #
 #   If you are only building threaded programs, you may wish to use these
 #   variables in your default LIBS, CFLAGS, and CC:
 #
 #     LIBS="$PTHREAD_LIBS $LIBS"
 #     CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+#     CXXFLAGS="$CXXFLAGS $PTHREAD_CFLAGS"
 #     CC="$PTHREAD_CC"
+#     CXX="$PTHREAD_CXX"
 #
 #   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant
 #   has a nonstandard name, this macro defines PTHREAD_CREATE_JOINABLE to
@@ -55,6 +59,7 @@
 #
 #   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
 #   Copyright (c) 2011 Daniel Richard G. <skunk@iSKUNK.ORG>
+#   Copyright (c) 2019 Marc Stevens <marc.stevens@cwi.nl>
 #
 #   This program is free software: you can redistribute it and/or modify it
 #   under the terms of the GNU General Public License as published by the
@@ -67,7 +72,7 @@
 #   Public License for more details.
 #
 #   You should have received a copy of the GNU General Public License along
-#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
 #
 #   As a special exception, the respective Autoconf Macro's copyright owner
 #   gives unlimited permission to copy, distribute and modify the configure
@@ -82,7 +87,7 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 23
+#serial 31
 
 AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
 AC_DEFUN([AX_PTHREAD], [
@@ -104,6 +109,7 @@ if test "x$PTHREAD_CFLAGS$PTHREAD_LIBS" != "x"; then
         ax_pthread_save_CFLAGS="$CFLAGS"
         ax_pthread_save_LIBS="$LIBS"
         AS_IF([test "x$PTHREAD_CC" != "x"], [CC="$PTHREAD_CC"])
+        AS_IF([test "x$PTHREAD_CXX" != "x"], [CXX="$PTHREAD_CXX"])
         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
         LIBS="$PTHREAD_LIBS $LIBS"
         AC_MSG_CHECKING([for pthread_join using $CC $PTHREAD_CFLAGS $PTHREAD_LIBS])
@@ -123,10 +129,12 @@ fi
 # (e.g. DEC) have both -lpthread and -lpthreads, where one of the
 # libraries is broken (non-POSIX).
 
-# Create a list of thread flags to try.  Items starting with a "-" are
-# C compiler flags, and other items are library names, except for "none"
-# which indicates that we try without any flags at all, and "pthread-config"
-# which is a program returning the flags for the Pth emulation library.
+# Create a list of thread flags to try. Items with a "," contain both
+# C compiler flags (before ",") and linker flags (after ","). Other items
+# starting with a "-" are C compiler flags, and remaining items are
+# library names, except for "none" which indicates that we try without
+# any flags at all, and "pthread-config" which is a program returning
+# the flags for the Pth emulation library.
 
 ax_pthread_flags="pthreads none -Kthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
 
@@ -194,14 +202,47 @@ case $host_os in
         # that too in a future libc.)  So we'll check first for the
         # standard Solaris way of linking pthreads (-mt -lpthread).
 
-        ax_pthread_flags="-mt,pthread pthread $ax_pthread_flags"
+        ax_pthread_flags="-mt,-lpthread pthread $ax_pthread_flags"
         ;;
 esac
 
+# Are we compiling with Clang?
+
+AC_CACHE_CHECK([whether $CC is Clang],
+    [ax_cv_PTHREAD_CLANG],
+    [ax_cv_PTHREAD_CLANG=no
+     # Note that Autoconf sets GCC=yes for Clang as well as GCC
+     if test "x$GCC" = "xyes"; then
+        AC_EGREP_CPP([AX_PTHREAD_CC_IS_CLANG],
+            [/* Note: Clang 2.7 lacks __clang_[a-z]+__ */
+#            if defined(__clang__) && defined(__llvm__)
+             AX_PTHREAD_CC_IS_CLANG
+#            endif
+            ],
+            [ax_cv_PTHREAD_CLANG=yes])
+     fi
+    ])
+ax_pthread_clang="$ax_cv_PTHREAD_CLANG"
+
+
 # GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC)
 
+# Note that for GCC and Clang -pthread generally implies -lpthread,
+# except when -nostdlib is passed.
+# This is problematic using libtool to build C++ shared libraries with pthread:
+# [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25460
+# [2] https://bugzilla.redhat.com/show_bug.cgi?id=661333
+# [3] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=468555
+# To solve this, first try -pthread together with -lpthread for GCC
+
 AS_IF([test "x$GCC" = "xyes"],
-      [ax_pthread_flags="-pthread -pthreads $ax_pthread_flags"])
+      [ax_pthread_flags="-pthread,-lpthread -pthread -pthreads $ax_pthread_flags"])
+
+# Clang takes -pthread (never supported any other flag), but we'll try with -lpthread first
+
+AS_IF([test "x$ax_pthread_clang" = "xyes"],
+      [ax_pthread_flags="-pthread,-lpthread -pthread"])
+
 
 # The presence of a feature test macro requesting re-entrant function
 # definitions is, on some systems, a strong hint that pthreads support is
@@ -224,25 +265,86 @@ AS_IF([test "x$ax_pthread_check_macro" = "x--"],
       [ax_pthread_check_cond=0],
       [ax_pthread_check_cond="!defined($ax_pthread_check_macro)"])
 
-# Are we compiling with Clang?
 
-AC_CACHE_CHECK([whether $CC is Clang],
-    [ax_cv_PTHREAD_CLANG],
-    [ax_cv_PTHREAD_CLANG=no
-     # Note that Autoconf sets GCC=yes for Clang as well as GCC
-     if test "x$GCC" = "xyes"; then
-        AC_EGREP_CPP([AX_PTHREAD_CC_IS_CLANG],
-            [/* Note: Clang 2.7 lacks __clang_[a-z]+__ */
-#            if defined(__clang__) && defined(__llvm__)
-             AX_PTHREAD_CC_IS_CLANG
-#            endif
-            ],
-            [ax_cv_PTHREAD_CLANG=yes])
-     fi
-    ])
-ax_pthread_clang="$ax_cv_PTHREAD_CLANG"
+if test "x$ax_pthread_ok" = "xno"; then
+for ax_pthread_try_flag in $ax_pthread_flags; do
+
+        case $ax_pthread_try_flag in
+                none)
+                AC_MSG_CHECKING([whether pthreads work without any flags])
+                ;;
+
+                *,*)
+                PTHREAD_CFLAGS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\1/"`
+                PTHREAD_LIBS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\2/"`
+                AC_MSG_CHECKING([whether pthreads work with "$PTHREAD_CFLAGS" and "$PTHREAD_LIBS"])
+                ;;
+
+                -*)
+                AC_MSG_CHECKING([whether pthreads work with $ax_pthread_try_flag])
+                PTHREAD_CFLAGS="$ax_pthread_try_flag"
+                ;;
+
+                pthread-config)
+                AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
+                AS_IF([test "x$ax_pthread_config" = "xno"], [continue])
+                PTHREAD_CFLAGS="`pthread-config --cflags`"
+                PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
+                ;;
+
+                *)
+                AC_MSG_CHECKING([for the pthreads library -l$ax_pthread_try_flag])
+                PTHREAD_LIBS="-l$ax_pthread_try_flag"
+                ;;
+        esac
+
+        ax_pthread_save_CFLAGS="$CFLAGS"
+        ax_pthread_save_LIBS="$LIBS"
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+
+        # Check for various functions.  We must include pthread.h,
+        # since some functions may be macros.  (On the Sequent, we
+        # need a special flag -Kthread to make this header compile.)
+        # We check for pthread_join because it is in -lpthread on IRIX
+        # while pthread_create is in libc.  We check for pthread_attr_init
+        # due to DEC craziness with -lpthreads.  We check for
+        # pthread_cleanup_push because it is one of the few pthread
+        # functions on Solaris that doesn't have a non-functional libc stub.
+        # We try pthread_create on general principles.
+
+        AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
+#                       if $ax_pthread_check_cond
+#                        error "$ax_pthread_check_macro must be defined"
+#                       endif
+                        static void *some_global = NULL;
+                        static void routine(void *a)
+                          {
+                             /* To avoid any unused-parameter or
+                                unused-but-set-parameter warning.  */
+                             some_global = a;
+                          }
+                        static void *start_routine(void *a) { return a; }],
+                       [pthread_t th; pthread_attr_t attr;
+                        pthread_create(&th, 0, start_routine, 0);
+                        pthread_join(th, 0);
+                        pthread_attr_init(&attr);
+                        pthread_cleanup_push(routine, 0);
+                        pthread_cleanup_pop(0) /* ; */])],
+            [ax_pthread_ok=yes],
+            [])
+
+        CFLAGS="$ax_pthread_save_CFLAGS"
+        LIBS="$ax_pthread_save_LIBS"
+
+        AC_MSG_RESULT([$ax_pthread_ok])
+        AS_IF([test "x$ax_pthread_ok" = "xyes"], [break])
+
+        PTHREAD_LIBS=""
+        PTHREAD_CFLAGS=""
+done
+fi
 
-ax_pthread_clang_warning=no
 
 # Clang needs special handling, because older versions handle the -pthread
 # option in a rather... idiosyncratic way
@@ -261,11 +363,6 @@ if test "x$ax_pthread_clang" = "xyes"; then
         # -pthread does define _REENTRANT, and while the Darwin headers
         # ignore this macro, third-party headers might not.)
 
-        PTHREAD_CFLAGS="-pthread"
-        PTHREAD_LIBS=
-
-        ax_pthread_ok=yes
-
         # However, older versions of Clang make a point of warning the user
         # that, in an invocation where only linking and no compilation is
         # taking place, the -pthread option has no effect ("argument unused
@@ -294,7 +391,7 @@ if test "x$ax_pthread_clang" = "xyes"; then
              # step
              ax_pthread_save_ac_link="$ac_link"
              ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
-             ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"`
+             ax_pthread_link_step=`AS_ECHO(["$ac_link"]) | sed "$ax_pthread_sed"`
              ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
              ax_pthread_save_CFLAGS="$CFLAGS"
              for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
@@ -320,78 +417,7 @@ if test "x$ax_pthread_clang" = "xyes"; then
 
 fi # $ax_pthread_clang = yes
 
-if test "x$ax_pthread_ok" = "xno"; then
-for ax_pthread_try_flag in $ax_pthread_flags; do
-
-        case $ax_pthread_try_flag in
-                none)
-                AC_MSG_CHECKING([whether pthreads work without any flags])
-                ;;
-
-                -mt,pthread)
-                AC_MSG_CHECKING([whether pthreads work with -mt -lpthread])
-                PTHREAD_CFLAGS="-mt"
-                PTHREAD_LIBS="-lpthread"
-                ;;
-
-                -*)
-                AC_MSG_CHECKING([whether pthreads work with $ax_pthread_try_flag])
-                PTHREAD_CFLAGS="$ax_pthread_try_flag"
-                ;;
-
-                pthread-config)
-                AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
-                AS_IF([test "x$ax_pthread_config" = "xno"], [continue])
-                PTHREAD_CFLAGS="`pthread-config --cflags`"
-                PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
-                ;;
-
-                *)
-                AC_MSG_CHECKING([for the pthreads library -l$ax_pthread_try_flag])
-                PTHREAD_LIBS="-l$ax_pthread_try_flag"
-                ;;
-        esac
-
-        ax_pthread_save_CFLAGS="$CFLAGS"
-        ax_pthread_save_LIBS="$LIBS"
-        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
-        LIBS="$PTHREAD_LIBS $LIBS"
-
-        # Check for various functions.  We must include pthread.h,
-        # since some functions may be macros.  (On the Sequent, we
-        # need a special flag -Kthread to make this header compile.)
-        # We check for pthread_join because it is in -lpthread on IRIX
-        # while pthread_create is in libc.  We check for pthread_attr_init
-        # due to DEC craziness with -lpthreads.  We check for
-        # pthread_cleanup_push because it is one of the few pthread
-        # functions on Solaris that doesn't have a non-functional libc stub.
-        # We try pthread_create on general principles.
-
-        AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
-#                       if $ax_pthread_check_cond
-#                        error "$ax_pthread_check_macro must be defined"
-#                       endif
-                        static void routine(void *a) { a = 0; }
-                        static void *start_routine(void *a) { return a; }],
-                       [pthread_t th; pthread_attr_t attr;
-                        pthread_create(&th, 0, start_routine, 0);
-                        pthread_join(th, 0);
-                        pthread_attr_init(&attr);
-                        pthread_cleanup_push(routine, 0);
-                        pthread_cleanup_pop(0) /* ; */])],
-            [ax_pthread_ok=yes],
-            [])
-
-        CFLAGS="$ax_pthread_save_CFLAGS"
-        LIBS="$ax_pthread_save_LIBS"
 
-        AC_MSG_RESULT([$ax_pthread_ok])
-        AS_IF([test "x$ax_pthread_ok" = "xyes"], [break])
-
-        PTHREAD_LIBS=""
-        PTHREAD_CFLAGS=""
-done
-fi
 
 # Various other checks:
 if test "x$ax_pthread_ok" = "xyes"; then
@@ -438,7 +464,8 @@ if test "x$ax_pthread_ok" = "xyes"; then
         AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
             [ax_cv_PTHREAD_PRIO_INHERIT],
             [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]],
-                                             [[int i = PTHREAD_PRIO_INHERIT;]])],
+                                             [[int i = PTHREAD_PRIO_INHERIT;
+                                               return i;]])],
                             [ax_cv_PTHREAD_PRIO_INHERIT=yes],
                             [ax_cv_PTHREAD_PRIO_INHERIT=no])
             ])
@@ -460,18 +487,28 @@ if test "x$ax_pthread_ok" = "xyes"; then
                     [#handle absolute path differently from PATH based program lookup
                      AS_CASE(["x$CC"],
                          [x/*],
-                         [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])],
-                         [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])])
+                         [
+			   AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])
+			   AS_IF([test "x${CXX}" != "x"], [AS_IF([AS_EXECUTABLE_P([${CXX}_r])],[PTHREAD_CXX="${CXX}_r"])])
+			 ],
+                         [
+			   AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])
+			   AS_IF([test "x${CXX}" != "x"], [AC_CHECK_PROGS([PTHREAD_CXX],[${CXX}_r],[$CXX])])
+			 ]
+                     )
+                    ])
                 ;;
             esac
         fi
 fi
 
 test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
+test -n "$PTHREAD_CXX" || PTHREAD_CXX="$CXX"
 
 AC_SUBST([PTHREAD_LIBS])
 AC_SUBST([PTHREAD_CFLAGS])
 AC_SUBST([PTHREAD_CC])
+AC_SUBST([PTHREAD_CXX])
 
 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
 if test "x$ax_pthread_ok" = "xyes"; then
@@ -483,3 +520,4 @@ else
 fi
 AC_LANG_POP
 ])dnl AX_PTHREAD
+
diff --git a/packages/ubuntu/Makefile.in b/packages/ubuntu/Makefile.in
index 13dfa7298..f1f0fdfda 100644
--- a/packages/ubuntu/Makefile.in
+++ b/packages/ubuntu/Makefile.in
@@ -6,7 +6,7 @@ ndpi:
 	mkdir -p ./debian/ndpi-tmp ./debian/ndpi-dev-tmp
 	mkdir -p  ./debian/ndpi-tmp/usr/lib ./debian/ndpi-tmp/usr/bin 
 	mkdir -p ./debian/ndpi-dev-tmp/usr/lib ./debian/ndpi-dev-tmp/usr/include/ndpi ./debian/ndpi-dev-tmp/usr/lib/pkgconfig
-	cd ${NDPI_HOME}; ./autogen.sh; ./configure; make
+	cd ${NDPI_HOME}; ./autogen.sh; ./configure; $(MAKE)
 	cp $(NDPI_HOME)/src/lib/libndpi.so.@NDPI_VERS@ ./debian/ndpi-tmp/usr/lib/
 	cd ./debian/ndpi-tmp/usr/lib/; ln -s libndpi.so.@NDPI_VERS@ libndpi.so; cd -
 	cd ./debian/ndpi-tmp/usr/lib/; ln -s libndpi.so.@NDPI_VERS@ libndpi.so.@MAJOR_RELEASE@; cd -
@@ -33,11 +33,11 @@ ndpi:
 	@echo "-------------------------------"
 
 distclean:
-	-cd ${NDPI_HOME} && make distclean
+	-cd ${NDPI_HOME} && $(MAKE) distclean
 
 install:
-	cd ${NDPI_HOME}; make install DESTDIR="${NDPI_BUILD}/debian/tmp" AM_UPDATE_INFO_DIR=no
+	cd ${NDPI_HOME}; $(MAKE) install DESTDIR="${NDPI_BUILD}/debian/tmp" AM_UPDATE_INFO_DIR=no
 
 clean:
-	-cd ${NDPI_HOME} && make clean
+	-cd ${NDPI_HOME} && $(MAKE) clean
 	-rm -rf *~ *deb ./usr ./debian/ndpi ./debian/ndpi-dev ./debian/ndpi ./debian/ndpi-dev
diff --git a/python/Makefile.in b/python/Makefile.in
index a3bcd5da3..3b976804a 100644
--- a/python/Makefile.in
+++ b/python/Makefile.in
@@ -2,7 +2,8 @@ CC=@CC@
 CFLAGS=-I. -I../src/include -I./src/lib/third_party/include @CFLAGS@ @CUSTOM_NDPI@ -shared
 #LIBNDPI=../src/lib/libndpi.so.@NDPI_VERSION_SHORT@
 LIBNDPI=../src/lib/libndpi.a
-LDFLAGS=$(CFILE) $(LIBNDPI) -lpcap  @LIBS@ @ADDITIONAL_LIBS@
+LDFLAGS=@LDFLAGS@
+LIBS=$(CFILE) $(LIBNDPI) -lpcap @LIBS@ @ADDITIONAL_LIBS@
 SHARE = -soname,ndpi_wrap
 SO=ndpi_wrap.so
 OBJS = ndpi_wrap.o
@@ -19,7 +20,7 @@ endif
 all: $(SO)
 
 $(SO): $(CFILE) $(LIBNDPI) Makefile
-	$(CC) $(CFLAGS) -Wl,$(SHARE) -o $@ $(PIC) $(LDFLAGS)
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $(PIC) -Wl,$(SHARE) -o $@ $(LIBS)
 #	ln -s $(LIBNDPI) .
 
 clean:
diff --git a/src/lib/Makefile.in b/src/lib/Makefile.in
index 56b9628c0..e3a3f9a9a 100644
--- a/src/lib/Makefile.in
+++ b/src/lib/Makefile.in
@@ -5,17 +5,18 @@
 # cd src/lib
 # make Makefile
 #
-
+AR = @AR@
+CC = @CC@
+RANLIB = @RANLIB@
 #
 # Installation directories
 #
 prefix     = @prefix@
 libdir     = ${prefix}/lib
 includedir = ${prefix}/include/ndpi
-CC         = @GNU_PREFIX@@CC@
 CFLAGS     += -fPIC -DPIC -I../include -Ithird_party/include -DNDPI_LIB_COMPILATION @CFLAGS@ @CUSTOM_NDPI@
-LDFLAGS    = @LDFLAGS@ @ADDITIONAL_LIBS@ @LIBS@
-RANLIB     = @GNU_PREFIX@ranlib
+LDFLAGS    = @LDFLAGS@
+LIBS       = @ADDITIONAL_LIBS@ @LIBS@
 
 OBJECTS   = $(patsubst protocols/%.c, protocols/%.o, $(wildcard protocols/*.c)) $(patsubst third_party/src/%.c, third_party/src/%.o, $(wildcard third_party/src/*.c)) $(patsubst ./%.c, ./%.o, $(wildcard ./*.c))
 HEADERS   = $(wildcard ../include/*.h)
@@ -47,16 +48,16 @@ all: $(NDPI_LIBS)
 ndpi_main.c: ndpi_content_match.c.inc
 
 $(NDPI_LIB_STATIC): $(OBJECTS)
-	   @GNU_PREFIX@ar rc $@ $(OBJECTS)
+	   $(AR) rc $@ $(OBJECTS)
 	   $(RANLIB) $@      
 
 $(NDPI_LIB_SHARED): $(OBJECTS)
-	$(CC) -shared -fPIC $(SONAME_FLAG) -o $@ $(OBJECTS) $(LDFLAGS)
+	$(CC) -shared -fPIC $(SONAME_FLAG) -o $@ $(LDFLAGS) $(OBJECTS) $(LIBS)
 	ln -fs $(NDPI_LIB_SHARED) $(NDPI_LIB_SHARED_BASE)
 	ln -fs $(NDPI_LIB_SHARED) $(NDPI_LIB_SHARED_BASE).$(NDPI_VERSION_MAJOR)
 
 %.o: %.c $(HEADERS) Makefile
-	$(CC) $(CFLAGS) -c $< -o $@
+	$(CC) $(CPPFLAGS) $(CFLAGS) -c $< -o $@
 
 clean:
 	/bin/rm -f $(NDPI_LIB_STATIC) $(OBJECTS) *.o *.so *.lo libndpi.so*
diff --git a/tests/dga/Makefile.in b/tests/dga/Makefile.in
index 2376abbbe..e2846830e 100644
--- a/tests/dga/Makefile.in
+++ b/tests/dga/Makefile.in
@@ -6,7 +6,8 @@ SRCHOME=../../src
 
 CFLAGS=-g -fPIC -DPIC -I$(SRCHOME)/include @JSONC_CFLAGS@ @PCAP_INC@ @CFLAGS@
 LIBNDPI=$(SRCHOME)/lib/libndpi.a
-LDFLAGS=$(LIBNDPI) @PCAP_LIB@ @LIBS@ @ADDITIONAL_LIBS@ @JSONC_LIBS@ -lpthread @LDFLAGS@
+LIBS=$(LIBNDPI) @PCAP_LIB@ @LIBS@ @ADDITIONAL_LIBS@ @JSONC_LIBS@ -lpthread
+LDFLAGS=@LDFLAGS@
 HEADERS=$(SRCHOME)/include/ndpi_api.h $(SRCHOME)/include/ndpi_typedefs.h $(SRCHOME)/include/ndpi_protocol_ids.h
 OBJS=dga_evaluate
 PREFIX?=@prefix@
@@ -23,10 +24,10 @@ EXECUTABLE_SOURCES := dga_evaluate.c
 COMMON_SOURCES := $(filter-out $(EXECUTABLE_SOURCES),$(wildcard *.c ))
 
 dga_evaluate: $(LIBNDPI) dga_evaluate.o
-	$(CC) $(CFLAGS) dga_evaluate.o -o $@ $(LDFLAGS)
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) dga_evaluate.o $(LIBS) -o $@
 
 %.o: %.c $(HEADERS) Makefile
-	$(CC) $(CFLAGS) -c $< -o $@
+	$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@
 
 clean:
 	/bin/rm -f *.o dga_evaluate
diff --git a/tests/unit/Makefile.in b/tests/unit/Makefile.in
index 98a3d67f4..b2f779fd3 100644
--- a/tests/unit/Makefile.in
+++ b/tests/unit/Makefile.in
@@ -6,7 +6,8 @@ SRCHOME=../../src
 
 CFLAGS=-g -fPIC -DPIC -I$(SRCHOME)/include @JSONC_CFLAGS@ @PCAP_INC@ @CFLAGS@
 LIBNDPI=$(SRCHOME)/lib/libndpi.a
-LDFLAGS=$(LIBNDPI) @PCAP_LIB@ @LIBS@ @ADDITIONAL_LIBS@ @JSONC_LIBS@ -lpthread @LDFLAGS@
+LIBS=$(LIBNDPI) @PCAP_LIB@ @LIBS@ @ADDITIONAL_LIBS@ @JSONC_LIBS@ -lpthread
+LDFLAGS=@LDFLAGS@
 HEADERS=$(SRCHOME)/include/ndpi_api.h $(SRCHOME)/include/ndpi_typedefs.h $(SRCHOME)/include/ndpi_protocol_ids.h
 OBJS=unit
 PREFIX?=@prefix@
@@ -23,10 +24,10 @@ EXECUTABLE_SOURCES := unit.c
 COMMON_SOURCES := $(filter-out $(EXECUTABLE_SOURCES),$(wildcard *.c ))
 
 unit: $(LIBNDPI) unit.o
-	$(CC) $(CFLAGS) unit.o -o $@ $(LDFLAGS)
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) unit.o $(LIBS) -o $@
 
 %.o: %.c $(HEADERS) Makefile
-	$(CC) $(CFLAGS) -c $< -o $@
+	$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@
 
 clean:
 	/bin/rm -f *.o unit