mpy-cross: Fix Makefile to handle gc-sections linker flags on OS X.

mpy-cross/Makefile

@@ -37,13 +37,12 @@ endif
 ifeq ($(UNAME_S),Darwin)
 CC = clang
 # Use clang syntax for map file
-LDFLAGS_ARCH = -Wl,-map,$@.map
+LDFLAGS_ARCH = -Wl,-map,$@.map -Wl,-dead_strip
 else
 # Use gcc syntax for map file
-LDFLAGS_ARCH = -Wl,-Map=$@.map,--cref
+LDFLAGS_ARCH = -Wl,-Map=$@.map,--cref -Wl,--gc-sections
 endif
 LDFLAGS = $(LDFLAGS_MOD) $(LDFLAGS_ARCH) -lm $(LDFLAGS_EXTRA)
-LDFLAGS += -Wl,--gc-sections
 
 # source files
 SRC_C = \