diff -up rpc2-2.10/rp2gen/Makefile.am.cflags rpc2-2.10/rp2gen/Makefile.am

--- rpc2-2.10/rp2gen/Makefile.am.cflags	2020-08-10 14:41:30.664876095 -0400

+++ rpc2-2.10/rp2gen/Makefile.am	2020-08-10 14:41:44.903843414 -0400

@@ -6,7 +6,7 @@ AM_YFLAGS= -d

 INCLUDES = -I$(top_builddir)/include -I$(top_srcdir)/include -I$(srcdir) -I.

 .c.o:

-	$(NATIVECC) $(INCLUDES) -c $<

+	$(NATIVECC) $(CFLAGS) $(INCLUDES) -c $<

 bin_PROGRAMS = rp2gen

diff -up rpc2-2.10/rp2gen/Makefile.in.cflags rpc2-2.10/rp2gen/Makefile.in

--- rpc2-2.10/rp2gen/Makefile.in.cflags	2020-08-10 14:42:35.839726505 -0400

+++ rpc2-2.10/rp2gen/Makefile.in	2020-08-10 14:42:44.687706199 -0400

@@ -556,7 +556,7 @@ uninstall-am: uninstall-binPROGRAMS

 .c.o:

-	$(NATIVECC) $(INCLUDES) -c $<

+	$(NATIVECC) $(CFLAGS) $(INCLUDES) -c $<

 rp2gen_parser.h: rp2gen_parser.c

 rp2gen_lexer.c: rp2gen_parser.h