firmware-utils: mkdlinkfw: compile as gnu99

Compile as gnu99 to fix the build.

Signed-off-by: Mathias Kresin <[email protected]>

tools/firmware-utils/Makefile

@@ -81,7 +81,7 @@ define Host/Compile
 	$(call cc,mkbuffaloimg, -Wall)
 	$(call cc,zyimage, -Wall)
 	$(call cc,mkdhpimg buffalo-lib, -Wall)
-	$(call cc,mkdlinkfw mkdlinkfw-lib, -lz -Wall)
+	$(call cc,mkdlinkfw mkdlinkfw-lib, -lz -Wall --std=gnu99)
 endef
 
 define Host/Install