build: ASLR hardening use $(FPIC)

Signed-off-by: Kevin Darbyshire-Bryant <[email protected]>

include/hardening.mk

@@ -18,7 +18,7 @@ ifdef CONFIG_PKG_CHECK_FORMAT_SECURITY
 endif
 ifdef CONFIG_PKG_ASLR_PIE
   ifeq ($(strip $(PKG_ASLR_PIE)),1)
-    TARGET_CFLAGS += -fPIC
+    TARGET_CFLAGS += $(FPIC)
     TARGET_LDFLAGS += -specs=$(INCLUDE_DIR)/hardened-ld-pie.specs
   endif
 endif