sys-fs/gfs2-utils: avoid adding -D_FORTIFY_SOURCE=2 to CPPFLAGS

Closes: https://bugs.gentoo.org/944282
Signed-off-by: Alexander Golubev <fatzer2@gmail.com>

sys-fs/gfs2-utils/gfs2-utils-3.5.1-r1.ebuild

@@ -40,7 +40,9 @@ src_prepare() {
 	eapply "${FILESDIR}"/gfs2_withdraw_helper.patch
 	eapply "${FILESDIR}"/python3.patch
 
-	sed -i '/^CFLAGS=/s!\$\(GDB_FLAGS\|OPT_CFLAGS\)\s*!!g' configure.ac || die
+	sed -e '/^CFLAGS=/s!\s*\$\(GDB_FLAGS\|OPT_CFLAGS\)!!g' \
+		-e '/^CPPFLAGS=/s!\s*\$OPT_CPPFLAGS!!' \
+		-i configure.ac || die
 
 	default