Allow more control over cflags in order to address this issue:
https://bugs.gentoo.org/show_bug.cgi?id=194681

--- /usr/portage/app-emulation/qemu-softmmu/qemu-softmmu-0.9.1-r1.ebuild.orig   2008-05-12 16:40:58.000000000 +0200
+++ /usr/portage/app-emulation/qemu-softmmu/qemu-softmmu-0.9.1-r1.ebuild        2008-05-12 16:14:32.000000000 +0200
@@ -48,6 +48,7 @@ src_unpack() {
	# Alter target makefiles to accept CFLAGS set via flag-o.
	sed -i 's/^\(C\|OP_C\|HELPER_C\)FLAGS=/\1FLAGS+=/' \
		Makefile Makefile.target tests/Makefile
+	sed -i 's/^OP_CFLAGS *:= */OP_CFLAGS:=$(HACK_CFLAGS) /' Makefile.target
	# Ensure mprotect restrictions are relaxed for emulator binaries
	[[ -x /sbin/paxctl ]] && \
		sed -i 's/^VL_LDFLAGS=$/VL_LDFLAGS=-Wl,-z,execheap/' \
@@ -61,6 +62,7 @@ src_unpack() {
 src_compile() {
	#Let the application set its cflags
	unset CFLAGS
+	export CFLAGS="${HACK_CFLAGS}"
 
	# Switch off hardened tech
	filter-flags -fpie -fstack-protector