--- a/CCache/Makefile.in
+++ b/CCache/Makefile.in
@@ -14,6 +14,7 @@ NOSOFTLINKSTEST=
 
 CC=@CC@
 CFLAGS=@CFLAGS@ -I.
+CPPFLAGS=@CPPFLAGS@
 SWIG=swig
 SWIG_LIB=../$(srcdir)/../Lib
 EXEEXT=@EXEEXT@
