diff --git a/m4/boinc_platform.m4 b/m4/boinc_platform.m4
index 9e647114ac..f1eaf33276 100644
--- a/m4/boinc_platform.m4
+++ b/m4/boinc_platform.m4
@@ -6,7 +6,7 @@ AC_DEFUN([BOINC_PLATFORM],[
 	      [boinc_platform=])
   AC_MSG_CHECKING([boinc platform])
   if test -z "${boinc_platform}" ; then
-    boinc_platform=`echo $target | $SED -e 's/redhat/pc/' -e 's/[0-9]$//' -e 's/[0-9]$//' -e 's/\.$//' -e 's/[0-9]$//'`
+    boinc_platform=`echo $target | $SED -e 's/redhat/pc/' -e 's/[[0-9]]$//' -e 's/[[0-9]]$//' -e 's/\.$//' -e 's/[[0-9]]$//'`
     case "${boinc_platform}" in
       sparc-sun-solaris)
     	if test "$COMPILER_MODEL_BITS" = "64" ; then