makefile fixes

Makefile.emscripten

@@ -95,13 +95,13 @@ _cmd_toggle_menu,_cmd_reload_config,_cmd_toggle_grab_mouse,_cmd_toggle_game_focu
 _cmd_set_volume,_cmd_set_shader,_cmd_cheat_set_code,_cmd_cheat_get_code,_cmd_cheat_toggle_index,_cmd_cheat_get_code_state,_cmd_cheat_realloc,\
 _cmd_cheat_get_size,_cmd_cheat_apply_cheats
 
-EXPORTS = callMain,FS,PATH,ERRNO_CODES,stringToNewUTF8,UTF8ToString
+EXPORTS := callMain,FS,PATH,ERRNO_CODES,stringToNewUTF8,UTF8ToString
 
 LIBS    := -s USE_ZLIB=1
 
 ifeq ($(HAVE_WASMFS), 1)
    LIBS += -s WASMFS -s FORCE_FILESYSTEM=1 -lfetchfs.js -lopfs.js
-   EXPORTS += ,FETCHFS,OPFS
+   EXPORTS := $(EXPORTS),FETCHFS,OPFS
 endif
 
 ifeq ($(HAVE_WORKER), 1)
@@ -208,8 +208,10 @@ RARCH_OBJ := $(addprefix $(OBJDIR)/,$(OBJ))
 
 all: $(TARGET)
 
-$(TARGET): $(RARCH_OBJ) $(libretro)
-	@$(if $(libretro), mv -f $(libretro) $(libretro_new),)
+$(libretro_new) : $(libretro)
+	mv -f $(libretro) $(libretro_new)
+
+$(TARGET): $(RARCH_OBJ) $(libretro_new)
 	@$(if $(Q), $(shell echo echo "LD $@ \<obj\> $(libretro_new) $(LIBS) $(LDFLAGS)"),)
 	$(Q)$(LD) -o $@ $(RARCH_OBJ) $(libretro_new) $(LIBS) $(LDFLAGS)