Index: libiberty/Makefile.in
--- libiberty/Makefile.in.orig
+++ libiberty/Makefile.in
@@ -111,7 +111,7 @@ installcheck: installcheck-subdir
 
 INCDIR=$(srcdir)/$(MULTISRCTOP)../include
 
-COMPILE.c = $(CC) -c @DEFS@ $(CFLAGS) $(CPPFLAGS) -I. -I$(INCDIR) \
+COMPILE.c = $(CC) -c @DEFS@ $(CFLAGS) -I. -I$(INCDIR) $(CPPFLAGS) \
                $(HDEFINES) @ac_libiberty_warn_cflags@ -D_GNU_SOURCE
 
 # Just to make sure we don't use a built-in rule with VPATH
