configure: Fix default -O2 being added when CFLAGS not set

Autoconf will set a default CFLAGS of "-g -O2" if CFLAGS is not set.
CFLAGS was defaulted to "" early in configure to prevent this. A recent
commit ad9ccf660 (configure: Fix various new autotools warnings) added
AC_USE_SYSTEM_EXTENSIONS, which pulls in the autoconf CFLAGS check,
before we default CFLAGS and thus setting the autoconf default for
CFLAGS. Move the default setting of CFLAGS to before AC_USE_SYSTEM_EXTENSIONS
so that autoconf will see CFLAGS as set and not give it a default.

CFLAGS is also moved above AC_CONFIG_AUX_DIR, because CFLAGS should be
defaulted to "" as soon as possible to catch any autoconf macros that try
to use some other default. Regardless, this currently has no effect as that
macro does not consider the CFLAGS variable.

Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Robbie Harwood <rharwood@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

diff --git a/configure.ac b/configure.ac
index 94653039c1d62a656ad70fe1a5c47e05b5f39ff3..57fb7094511062ffa8abd720af978a3347c76536 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -36,12 +36,12 @@ dnl description of the relationships between them.
 
 AC_INIT([GRUB],[2.11],[bug-grub@gnu.org])
 
-AC_USE_SYSTEM_EXTENSIONS
-AC_CONFIG_AUX_DIR([build-aux])
-
 # We don't want -g -O2 by default in CFLAGS
 : ${CFLAGS=""}
 
+AC_USE_SYSTEM_EXTENSIONS
+AC_CONFIG_AUX_DIR([build-aux])
+
 # Checks for build, host and target systems.
 AC_CANONICAL_BUILD
 AC_CANONICAL_HOST