Move C compiler warning (-W) flags from CFLAGS to AM_CFLAGS.

C compiler warning options added by the "configure" script have until
now been put into CFLAGS.  However that option is supposed to be reserved
for the user under Automake rules, so move them to AM_CFLAGS.

Besides increased adherence to Automake rules, this is useful because
AM_CFLAGS can be overridden on a per-target (e.g. program or library)
basis, whereas CFLAGS cannot.  In turn, building the sFlow library (which
will be added in an upcoming commit) requires overriding the compiler
flags to avoid some warning messages.  (By modifying the warning flags, we
avoid the need to modify the sFlow library in any way.)

diff --git a/Makefile.am b/Makefile.am
index add0e72a9886b02ea9d65c591745e9e78fa8a04d..de51e10f779794af0c9faa0af389e8fdb41d2bc7 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -16,6 +16,7 @@ AM_CPPFLAGS += -I $(top_srcdir)/include
 AM_CPPFLAGS += -I $(top_srcdir)/lib
 
 AM_CFLAGS = -Wstrict-prototypes
+AM_CFLAGS += $(WARNING_FLAGS)
 
 if NDEBUG
 AM_CPPFLAGS += -DNDEBUG

diff --git a/acinclude.m4 b/acinclude.m4
index 767414e604d1d4102ec604acdb38c1e14e39ba36..e37a316dffa97a99d069ed2bd0687f591deca7d9 100644 (file)
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -230,8 +230,9 @@ AC_DEFUN([OVS_CHECK_CC_OPTION],
 
 dnl OVS_ENABLE_OPTION([OPTION])
 dnl Check whether the given C compiler OPTION is accepted.
-dnl If so, add it to CFLAGS.
+dnl If so, add it to WARNING_FLAGS.
 dnl Example: OVS_ENABLE_OPTION([-Wdeclaration-after-statement])
 AC_DEFUN([OVS_ENABLE_OPTION], 
-  [OVS_CHECK_CC_OPTION([$1], [CFLAGS="$CFLAGS $1"])])
+  [OVS_CHECK_CC_OPTION([$1], [WARNING_FLAGS="$WARNING_FLAGS $1"])
+   AC_SUBST([WARNING_FLAGS])])
 dnl ----------------------------------------------------------------------