[Ltrace-devel] [PATCH 5/6] Switch CPPFLAGS and LDFLAGS to AM_ variants

[Zachary T Welch]

Like CFLAGS, CPPFLAGS and LDFLAGS should not be set directly by the
configure script, because the user can override them during 'make' (and
that will break the build).  Instead, the AM_CPPFLAGS and AM_LDFLAGS
variables must be used to set options from configure; so, make it so.

Signed-off-by: Zachary T Welch <zwelch at codesourcery.com>
---
 Makefile.am  |    2 +-
 configure.ac |   16 ++++++++++++----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index 61a0410..6c299d8 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -3,7 +3,7 @@ SUBDIRS = \
 	. \
 	testsuite
 
-AM_CPPFLAGS = \
+AM_CPPFLAGS += \
 	$(libelf_CFLAGS) \
 	-DSYSCONFDIR=\"$(sysconfdir)\"
 
diff --git a/configure.ac b/configure.ac
index d69f484..da9b797 100644
--- a/configure.ac
+++ b/configure.ac
@@ -66,13 +66,16 @@ AC_ARG_WITH(libunwind,
   [case "${withval}" in
   (yes|no) enable_libunwind=$withval;;
   (*) enable_libunwind=yes
-    CPPFLAGS="${CPPFLAGS} -I${withval}/include"
-    LDFLAGS="${LDFLAGS} -L${withval}/lib"
+    AM_CPPFLAGS="${AM_CPPFLAGS} -I${withval}/include"
+    AM_LDFLAGS="${AM_LDFLAGS} -L${withval}/lib"
     ;;
 esac],[enable_libunwind=maybe])
 
+saved_CPPFLAGS="${CPPFLAGS}"
+CPPFLAGS="${CPPFLAGS} ${AM_CPPFLAGS}"
 AC_CHECK_HEADERS([libunwind.h], [have_libunwind_h=yes])
 AC_CHECK_HEADERS([libunwind-ptrace.h], [have_libunwind_ptrace_h=yes])
+CPPFLAGS="${saved_CPPFLAGS}"
 
 AC_MSG_CHECKING([whether to use libunwind support])
 case "${enable_libunwind}" in
@@ -91,6 +94,8 @@ esac
 AC_MSG_RESULT([$enable_libunwind])
 
 if test x"$enable_libunwind" = xyes; then
+  saved_LDFLAGS="${LDFLAGS}"
+  LDFLAGS="${LDFLAGS} ${AM_LDFLAGS}"
   AC_CHECK_LIB(unwind, backtrace, libunwind_LIBS=-lunwind, libunwind_LIBS=)
   AC_SUBST(libunwind_LIBS)
   AC_CHECK_LIB(unwind-ptrace, _UPT_create, libunwind_ptrace_LIBS=-lunwind-ptrace, libunwind_ptrace_LIBS=)
@@ -108,6 +113,7 @@ if test x"$enable_libunwind" = xyes; then
   AC_CHECK_LIB(unwind-${UNWIND_ARCH}, _U${UNWIND_ARCH}_init_remote, libunwind_arch_LIBS=-lunwind-${UNWIND_ARCH}, libunwind_arch_LIBS=)
   AC_SUBST(libunwind_arch_LIBS)
   AC_DEFINE([HAVE_LIBUNWIND], [1], [we have libunwind])
+  LDFLAGS="${saved_LDFLAGS}"
 fi
 
 
@@ -135,8 +141,8 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <libelf.h>]], [[
 	[AC_MSG_RESULT([no])])
 CFLAGS="${saved_CFLAGS}"
 
-CPPFLAGS=" \
-	${CPPFLAGS} \
+AM_CPPFLAGS=" \
+	${AM_CPPFLAGS} \
 	-I\$(top_srcdir)/sysdeps/${HOST_OS}/${HOST_CPU} \
 	-I\$(top_srcdir)/sysdeps/${HOST_OS} \
 	-I\$(top_srcdir)/sysdeps \
@@ -209,7 +215,9 @@ if test x$enable_werror = xyes; then
     AM_CFLAGS="${AM_CFLAGS} -Werror"
 fi
 
+AC_SUBST(AM_CPPFLAGS)
 AC_SUBST(AM_CFLAGS)
+AC_SUBST(AM_LDFLAGS)
 
 AC_CONFIG_FILES([
 	Makefile
-- 
1.7.2.2