diff --git a/common.mk b/common.mk
index 69fc6e42af..0449d24dd5 100644
--- a/common.mk
+++ b/common.mk
@@ -213,7 +213,7 @@ mjit_config.h: Makefile
 
 $(TIMESTAMPDIR)/$(MJIT_HEADER:.h=)$(MJIT_HEADER_SUFFIX).time: probes.h vm.$(OBJEXT)
 	$(ECHO) building $(@F:.time=.h)
-	$(Q) $(CPP) $(MJIT_HEADER_FLAGS) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) -DMJIT_HEADER $(srcdir)/vm.c $(CPPOUTFLAG)$(@F:.time=.h).new
+	$(Q) $(CPP) -DMJIT_HEADER $(MJIT_HEADER_FLAGS) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(srcdir)/vm.c $(CPPOUTFLAG)$(@F:.time=.h).new
 	$(Q) $(IFCHANGE) "--timestamp=$@" $(@F:.time=.h) $(@F:.time=.h).new
 
 $(MJIT_HEADER:.h=)$(MJIT_HEADER_SUFFIX).h: $(TIMESTAMPDIR)/$(MJIT_HEADER:.h=)$(MJIT_HEADER_SUFFIX).time
diff --git a/gc.c b/gc.c
index be0dd701ff..a1e6bc4bc2 100644
--- a/gc.c
+++ b/gc.c
@@ -9452,7 +9452,7 @@ obj_info(VALUE obj)
 }
 #endif
 
-const char *
+MJIT_FUNC_EXPORTED const char *
 rb_obj_info(VALUE obj)
 {
     if (!rb_special_const_p(obj)) {