diff --git a/configure/os/CONFIG.solaris-sparc.solaris-sparc b/configure/os/CONFIG.solaris-sparc.solaris-sparc
index 8aa43d6f1..93fddc85c 100644
--- a/configure/os/CONFIG.solaris-sparc.solaris-sparc
+++ b/configure/os/CONFIG.solaris-sparc.solaris-sparc
@@ -13,7 +13,8 @@ CC = $(SPARCWORKS)/bin/cc
 CCC = $(SPARCWORKS)/bin/CC
 #CPP = $(CCC) -E
 #CPP = $(CCC) -P
-CPP = g++ -E
+CPP = g++ -x c -E
+
 RANLIB =
 # required by sun's C++ compiler
 AR = $(CCC) -xar -o