build: add -fno-plt to default cflags, it improves PIC code optimization

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

SVN-Revision: 48470

config/Config-devel.in

@@ -106,6 +106,7 @@ menuconfig DEVEL
 
 	config EXTRA_OPTIMIZATION
 		string "Additional compiler options" if DEVEL
+		default "-fno-caller-saves -fno-plt" if !CONFIG_EXTERNAL_TOOLCHAIN
 		default "-fno-caller-saves"
 		help
 		  Extra target-independent optimizations to use when building for the target.