Add common TARGET_FLAGS option to Makefile.

src/Makefile

@@ -162,7 +162,7 @@ XCFLAGS=
 #   CFLAGS   HOST_CFLAGS   TARGET_CFLAGS
 #   LDFLAGS  HOST_LDFLAGS  TARGET_LDFLAGS  TARGET_SHLDFLAGS
 #   LIBS     HOST_LIBS     TARGET_LIBS
-#   CROSS    HOST_SYS      TARGET_SYS
+#   CROSS    HOST_SYS      TARGET_SYS      TARGET_FLAGS
 #
 # Cross-compilation examples:
 #   make HOST_CC="gcc -m32" CROSS=i586-mingw32msvc- TARGET_SYS=Windows
@@ -206,9 +206,9 @@ TARGET_DYNXLDOPTS=
 TARGET_XCFLAGS= -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -U_FORTIFY_SOURCE
 TARGET_XLDFLAGS=
 TARGET_XLIBS= -lm
-TARGET_ACFLAGS= $(CCOPTIONS) $(TARGET_XCFLAGS) $(TARGET_ARCH) $(TARGET_CFLAGS)
-TARGET_ALDFLAGS= $(LDOPTIONS) $(TARGET_XLDFLAGS) $(TARGET_LDFLAGS)
-TARGET_ASHLDFLAGS= $(LDOPTIONS) $(TARGET_XSHLDFLAGS) $(TARGET_SHLDFLAGS)
+TARGET_ACFLAGS= $(CCOPTIONS) $(TARGET_XCFLAGS) $(TARGET_ARCH) $(TARGET_FLAGS) $(TARGET_CFLAGS)
+TARGET_ALDFLAGS= $(LDOPTIONS) $(TARGET_XLDFLAGS) $(TARGET_FLAGS) $(TARGET_LDFLAGS)
+TARGET_ASHLDFLAGS= $(LDOPTIONS) $(TARGET_XSHLDFLAGS) $(TARGET_FLAGS) $(TARGET_SHLDFLAGS)
 TARGET_ALIBS= $(TARGET_XLIBS) $(LIBS) $(TARGET_LIBS)
 
 ifneq (,$(findstring stack-protector,$(shell $(TARGET_CC) -dumpspecs)))