functions.sh: dont die if gcc is missing

abuild-sign does not use gcc.

fixes #9974

functions.sh.in

@@ -117,7 +117,7 @@ readconfig() {
 	USE_COLORS=${_USE_COLORS-$USE_COLORS}
 	USE_CCACHE=${_USE_CCACHE-$USE_CCACHE}
 
-	[ -z "$CBUILD" ] && CBUILD="$(gcc -dumpmachine)"
+	[ -z "$CBUILD" ] && CBUILD="$(${CC:-gcc} -dumpmachine 2>/dev/null || true)"
 	[ -z "$CHOST" ] && CHOST="$CBUILD"
 	[ -z "$CTARGET" ] && CTARGET="$CHOST"
 	[ "$(arch_to_hostspec $CBUILD)" != "unknown" ] && CBUILD="$(arch_to_hostspec $CBUILD)"

tests/functions.bats

@@ -0,0 +1,11 @@
+setup() {
+	export FUNCS=../functions.sh
+}
+
+@test "check if CBUILD is set" {
+	. $FUNCS && test -n "$CBUILD"
+}
+
+@test "check that missing gcc does not kill us" {
+	sh -e -c "CC=false; . $FUNCS && test -z \"$CBUILD\""
+}