diff --git a/Makefile.in b/Makefile.in
index d24c1af..b86e522 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -230,6 +229,7 @@ RAW_CXX_TARGET_EXPORTS = \
 
 NORMAL_TARGET_EXPORTS = \
 	$(BASE_TARGET_EXPORTS) \
+	CPP="$(CC_FOR_TARGET) -E"; export CPP; \
 	CXX="$(CXX_FOR_TARGET)"; export CXX;
 
 # Where to find GMP