diff --git a/aclocal.m4 b/aclocal.m4
index 85667d25d2fe79b744ac145cea1bc72a672cc79e..5b31f351ccc1b3dbbfa601a43e4ae5f8bcc084c3 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1,4 +1,4 @@
-# $Id: aclocal.m4,v 1.16 1998/02/12 12:11:53 simonm Exp $
+# $Id: aclocal.m4,v 1.17 1998/02/12 12:37:22 simonm Exp $
 #
 # Extra autoconf macros for the Glasgow fptools
 #
@@ -274,8 +274,8 @@ AC_DEFUN(AC_PROG_GNUCPP,
 [if test "$HaveGcc" = "YES"; then
 	echo > conftest.c
 	gcc -v -E conftest.c >/dev/null 2>conftest.out
-	echo '/(\S+(\/|\\)cpp)/ && print "[$]1";' > conftest.pl
-	ac_cv_gnu_cpp="`eval $PerlCmd -n conftest.pl conftest.out | tr '\\\' / `"
+	echo '/(\S+(\/|\\\\)cpp)/ && print "[$]1";' > conftest.pl
+	ac_cv_gnu_cpp="`eval $PerlCmd -n conftest.pl conftest.out`"
 	rm -fr conftest*
  else
 	# We need to be able to invoke CPP directly, preferably