configure: add -Werror to QEMU_CFLAGS early

We want all configure tests pass with -Werror if it is enabled. So we
need to update QEMU_CFLAGS early on to make sure we also pass it in to
all the compile test jobs.

This fixes a warning-became-error bug in nss for me with the default
configuration:

In file included from /usr/include/nss3/pkcs11t.h:1780,
                 from /usr/include/nss3/keythi.h:41,
                 from /usr/include/nss3/keyt.h:41,
                 from /usr/include/nss3/pk11pub.h:43,
                 from libcacard/vcard_emul_nss.c:21:
/usr/include/nss3/pkcs11n.h:365:26: error: "__GNUC_MINOR" is not defined
Signed-off-by: NAlexander Graf <agraf@suse.de>
Acked-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

configure

@@ -1139,10 +1139,26 @@ else
     exit 1
 fi
 
+# Consult white-list to determine whether to enable werror
+# by default.  Only enable by default for git builds
+z_version=`cut -f3 -d. $source_path/VERSION`
+
+if test -z "$werror" ; then
+    if test "$z_version" = "50" -a \
+        "$linux" = "yes" ; then
+        werror="yes"
+    else
+        werror="no"
+    fi
+fi
+
 gcc_flags="-Wold-style-declaration -Wold-style-definition -Wtype-limits"
 gcc_flags="-Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers $gcc_flags"
 gcc_flags="-Wmissing-include-dirs -Wempty-body -Wnested-externs $gcc_flags"
 gcc_flags="-fstack-protector-all -Wendif-labels $gcc_flags"
+if test "$werror" = "yes" ; then
+    gcc_flags="-Werror $gcc_flags"
+fi
 cat > $TMPC << EOF
 int main(void) { return 0; }
 EOF
@@ -2573,7 +2589,7 @@ if test "$libiscsi" != "no" ; then
 #include <iscsi/iscsi.h>
 int main(void) { iscsi_unmap_sync(NULL,0,0,0,NULL,0); return 0; }
 EOF
-  if compile_prog "-Werror" "-liscsi" ; then
+  if compile_prog "" "-liscsi" ; then
     libiscsi="yes"
     LIBS="$LIBS -liscsi"
   else
@@ -2877,19 +2893,6 @@ if test "$debug" = "no" ; then
   CFLAGS="-O2 -D_FORTIFY_SOURCE=2 $CFLAGS"
 fi
 
-# Consult white-list to determine whether to enable werror
-# by default.  Only enable by default for git builds
-z_version=`cut -f3 -d. $source_path/VERSION`
-
-if test -z "$werror" ; then
-    if test "$z_version" = "50" -a \
-        "$linux" = "yes" ; then
-        werror="yes"
-    else
-        werror="no"
-    fi
-fi
-
 # Disable zero malloc errors for official releases unless explicitly told to
 # enable/disable
 if test -z "$zero_malloc" ; then
@@ -2900,10 +2903,6 @@ if test -z "$zero_malloc" ; then
     fi
 fi
 
-if test "$werror" = "yes" ; then
-    QEMU_CFLAGS="-Werror $QEMU_CFLAGS"
-fi
-
 if test "$solaris" = "no" ; then
     if $ld --version 2>/dev/null | grep "GNU ld" >/dev/null 2>/dev/null ; then
         LDFLAGS="-Wl,--warn-common $LDFLAGS"