diff --git a/config/CONFIG.Vx b/config/CONFIG.Vx
index 16de8d78c..a0ff75930 100644
--- a/config/CONFIG.Vx
+++ b/config/CONFIG.Vx
@@ -40,7 +40,7 @@ GNU_LIB = $(VX_GNU_LIB_$(TORNADO))
 
 GCC = $(GNU_BIN)/cc$(CMPLR_SUFFIX) -B$(GNU_LIB)/gcc-lib/ -nostdinc
 AR = $(GNU_BIN)/ar$(CMPLR_SUFFIX)
-CPP = $(GNU_BIN)/cpp$(CMPLR_SUFFIX) -nostdinc
+CPP = $(GNU_BIN)/cc$(CMPLR_SUFFIX) -B$(GNU_LIB)/gcc-lib/ -nostdinc -x c -E
 RANLIB = $(GNU_BIN)/ranlib$(CMPLR_SUFFIX)
 LD = $(GNU_BIN)/ld$(CMPLR_SUFFIX) -r