From 8d33b26f4103e9f352c53a1c89f1cb4636d5f240 Mon Sep 17 00:00:00 2001
From: Murray Cumming <murrayc@murrayc.com>
Date: Fri, 10 Jul 2015 21:26:04 +0200
Subject: [PATCH] AX_PYTHON_DEVEL: provide PYTHON_LIBS, not PYTHON_LDFLAGS

Because -L and -l are LIBS arguments, not LDFLAGS arguments.
Calling it PYTHON_LDFLAGS suggested wrongly that they should be
used in LDFLAGS, which can cause the -L and -l arguments to
be ignored when they are not in the expected position in the list
of command line arguments. This is a problem, for instance,
with the command line generated by AC_LINK_IFELSE.
---
 m4/ax_python_devel.m4 | 43 +++++++++++++++++++++++--------------------
 1 file changed, 23 insertions(+), 20 deletions(-)

diff --git a/m4/ax_python_devel.m4 b/m4/ax_python_devel.m4
index 59a2ff0..a5b5ea8 100644
--- a/m4/ax_python_devel.m4
+++ b/m4/ax_python_devel.m4
@@ -12,7 +12,7 @@
 #   in your configure.ac.
 #
 #   This macro checks for Python and tries to get the include path to
-#   'Python.h'. It provides the $(PYTHON_CPPFLAGS) and $(PYTHON_LDFLAGS)
+#   'Python.h'. It provides the $(PYTHON_CPPFLAGS) and $(PYTHON_LIBS)
 #   output variables. It also exports $(PYTHON_EXTRA_LIBS) and
 #   $(PYTHON_EXTRA_LDFLAGS) for embedding Python in your code.
 #
@@ -99,7 +99,7 @@ AC_DEFUN([AX_PYTHON_DEVEL],[
 This version of the AC@&t@_PYTHON_DEVEL macro
 doesn't work properly with versions of Python before
 2.1.0. You may need to re-run configure, setting the
-variables PYTHON_CPPFLAGS, PYTHON_LDFLAGS, PYTHON_SITE_PKG,
+variables PYTHON_CPPFLAGS, PYTHON_LIBS, PYTHON_SITE_PKG,
 PYTHON_EXTRA_LIBS and PYTHON_EXTRA_LDFLAGS by hand.
 Moreover, to disable this check, set PYTHON_NOVERSIONCHECK
 to something else than an empty string.
@@ -172,7 +172,7 @@ $ac_distutils_result])
 	# Check for Python library path
 	#
 	AC_MSG_CHECKING([for Python library path])
-	if test -z "$PYTHON_LDFLAGS"; then
+	if test -z "$PYTHON_LIBS"; then
 		# (makes two attempts to ensure we've got a version number
 		# from the interpreter)
 		ac_python_version=`cat<<EOD | $PYTHON -
@@ -227,25 +227,25 @@ EOD`
 		then
 			# use the official shared library
 			ac_python_library=`echo "$ac_python_library" | sed "s/^lib//"`
-			PYTHON_LDFLAGS="-L$ac_python_libdir -l$ac_python_library"
+			PYTHON_LIBS="-L$ac_python_libdir -l$ac_python_library"
 		else
 			# old way: use libpython from python_configdir
 			ac_python_libdir=`$PYTHON -c \
 			  "from distutils.sysconfig import get_python_lib as f; \
 			  import os; \
 			  print (os.path.join(f(plat_specific=1, standard_lib=1), 'config'));"`
-			PYTHON_LDFLAGS="-L$ac_python_libdir -lpython$ac_python_version"
+			PYTHON_LIBS="-L$ac_python_libdir -lpython$ac_python_version"
 		fi
 
-		if test -z "PYTHON_LDFLAGS"; then
+		if test -z "PYTHON_LIBS"; then
 			AC_MSG_ERROR([
   Cannot determine location of your Python DSO. Please check it was installed with
-  dynamic libraries enabled, or try setting PYTHON_LDFLAGS by hand.
+  dynamic libraries enabled, or try setting PYTHON_LIBS by hand.
 			])
 		fi
 	fi
-	AC_MSG_RESULT([$PYTHON_LDFLAGS])
-	AC_SUBST([PYTHON_LDFLAGS])
+	AC_MSG_RESULT([$PYTHON_LIBS])
+	AC_SUBST([PYTHON_LIBS])
 
 	#
 	# Check for site packages
@@ -262,25 +262,25 @@ EOD`
 	# libraries which must be linked in when embedding
 	#
 	AC_MSG_CHECKING(python extra libraries)
-	if test -z "$PYTHON_EXTRA_LIBS"; then
-	   PYTHON_EXTRA_LIBS=`$PYTHON -c "import distutils.sysconfig; \
+	if test -z "$PYTHON_EXTRA_LDFLAGS"; then
+	   PYTHON_EXTRA_LDFLAGS=`$PYTHON -c "import distutils.sysconfig; \
                 conf = distutils.sysconfig.get_config_var; \
                 print (conf('LIBS') + ' ' + conf('SYSLIBS'))"`
 	fi
-	AC_MSG_RESULT([$PYTHON_EXTRA_LIBS])
-	AC_SUBST(PYTHON_EXTRA_LIBS)
+	AC_MSG_RESULT([$PYTHON_EXTRA_LDFLAGS])
+	AC_SUBST(PYTHON_EXTRA_LDFLAGS)
 
 	#
 	# linking flags needed when embedding
 	#
 	AC_MSG_CHECKING(python extra linking flags)
-	if test -z "$PYTHON_EXTRA_LDFLAGS"; then
-		PYTHON_EXTRA_LDFLAGS=`$PYTHON -c "import distutils.sysconfig; \
+	if test -z "$PYTHON_EXTRA_LIBS"; then
+		PYTHON_EXTRA_LIBS=`$PYTHON -c "import distutils.sysconfig; \
 			conf = distutils.sysconfig.get_config_var; \
 			print (conf('LINKFORSHARED'))"`
 	fi
-	AC_MSG_RESULT([$PYTHON_EXTRA_LDFLAGS])
-	AC_SUBST(PYTHON_EXTRA_LDFLAGS)
+	AC_MSG_RESULT([$PYTHON_EXTRA_LIBS])
+	AC_SUBST(PYTHON_EXTRA_LIBS)
 
 	#
 	# final check to see if everything compiles alright
@@ -288,8 +288,10 @@ EOD`
 	AC_MSG_CHECKING([consistency of all components of python development environment])
 	# save current global flags
 	ac_save_LIBS="$LIBS"
+	ac_save_LDFLAGS="$LDFLAGS"
 	ac_save_CPPFLAGS="$CPPFLAGS"
-	LIBS="$ac_save_LIBS $PYTHON_LDFLAGS $PYTHON_EXTRA_LDFLAGS $PYTHON_EXTRA_LIBS"
+	LIBS="$ac_save_LIBS $PYTHON_LIBS $PYTHON_EXTRA_LIBS $PYTHON_EXTRA_LIBS"
+	LDFLAGS="$ac_save_LDFLAGS $PYTHON_EXTRA_LDFLAGS"
 	CPPFLAGS="$ac_save_CPPFLAGS $PYTHON_CPPFLAGS"
 	AC_LANG_PUSH([C])
 	AC_LINK_IFELSE([
@@ -300,6 +302,7 @@ EOD`
 	# turn back to default flags
 	CPPFLAGS="$ac_save_CPPFLAGS"
 	LIBS="$ac_save_LIBS"
+	LDFLAGS="$ac_save_LDFLAGS"
 
 	AC_MSG_RESULT([$pythonexists])
 
@@ -307,8 +310,8 @@ EOD`
 	   AC_MSG_FAILURE([
   Could not link test program to Python. Maybe the main Python library has been
   installed in some non-standard library path. If so, pass it to configure,
-  via the LDFLAGS environment variable.
-  Example: ./configure LDFLAGS="-L/usr/non-standard-path/python/lib"
+  via the LIBS environment variable.
+  Example: ./configure LIBS="-L/usr/non-standard-path/python/lib"
   ============================================================================
    ERROR!
    You probably have to install the development version of the Python package
-- 
2.1.4

