diff --git a/gcc/fixincludes b/gcc/fixincludes
index c3b749c7ef7..413eefef5d4 100755
--- a/gcc/fixincludes
+++ b/gcc/fixincludes
@@ -43,11 +43,9 @@ fi
 
 echo 'Making directories:'
 cd ${INPUT}
-if $LINKS; then
-  files=`ls -LR | sed -n s/:$//p`
-else
-  files=`find . -type d -print | sed '/^.$/d'`
-fi
+# Find all directories and all symlinks that point to directories.
+files=`	find . -type d -print | sed '/^.$/d'
+	$LINKS && find . -type l -exec test -d '{}' \; -print`
 for file in $files; do
   rm -rf $LIB/$file
   if [ ! -d $LIB/$file ]
@@ -110,10 +108,12 @@ while [ $# != 0 ]; do
   for file in $files; do
 # This call to egrep is essential, since checking a file with egrep
 # is much faster than actually trying to fix it.
+# It is also essential that most files *not* match!
+# Thus, matching every #endif is unacceptable.
 # But the argument to egrep must be kept small, or many versions of egrep
 # won't be able to handle it.
 # rms: I removed `|#[el].*if.*[^/ 	]' because it made egrep fail.
-    if egrep '[ 	_]_IO|CTRL|#define.NULL|#[el]*if.*([0-9]|#e[nl]|sparc|vax|sun|pyr)' $file > /dev/null; then
+    if egrep '[ 	_]_IO|CTRL|#define.NULL|#[el]*if.*([0-9]|sparc|vax|sun|pyr)' $file > /dev/null; then
       echo Fixing $file
       if [ -r $file ]; then
 	cp $file $2/$file >/dev/null 2>&1	\
@@ -194,8 +194,8 @@ if [ -r ${LIB}/$file ]; then
   ex ${LIB}/$file <<EOF
   /size_t.*;/
   i
-#ifndef _SIZE_T
-#define _SIZE_T
+#ifndef _GCC_SIZE_T
+#define _GCC_SIZE_T
 .
   /size_t/+1
   i
@@ -203,8 +203,8 @@ if [ -r ${LIB}/$file ]; then
 .
   /ptrdiff_t.*;/
   i
-#ifndef _PTRDIFF_T
-#define _PTRDIFF_T
+#ifndef _GCC_PTRDIFF_T
+#define _GCC_PTRDIFF_T
 .
   /ptrdiff_t/+1
   i
@@ -212,8 +212,8 @@ if [ -r ${LIB}/$file ]; then
 .
   /wchar_t.*;/
   i
-#ifndef _WCHAR_T
-#define _WCHAR_T
+#ifndef _GCC_WCHAR_T
+#define _GCC_WCHAR_T
 .
   /wchar_t/+1
   i
@@ -239,8 +239,8 @@ if [ -r ${LIB}/$file ]; then
   ex ${LIB}/$file <<EOF
   /size_t.*;/
   i
-#ifndef _SIZE_T
-#define _SIZE_T
+#ifndef _GCC_SIZE_T
+#define _GCC_SIZE_T
 .
   /size_t/+1
   i
diff --git a/gcc/ginclude/stddef.h b/gcc/ginclude/stddef.h
index 9ceb4699fb2..ffd8c62908c 100644
--- a/gcc/ginclude/stddef.h
+++ b/gcc/ginclude/stddef.h
@@ -16,45 +16,57 @@
 /* Signed type of difference of two pointers.  */
 
 #ifndef _PTRDIFF_T	/* in case <sys/types.h> has defined it. */
+#ifndef _T_PTRDIFF_
 #ifndef _T_PTRDIFF
 #ifndef __PTRDIFF_T
 #ifndef _PTRDIFF_T_
 #ifndef ___int_ptrdiff_t_h
+#ifndef _GCC_PTRDIFF_T
 #define _PTRDIFF_T
+#define _T_PTRDIFF_
 #define _T_PTRDIFF
 #define __PTRDIFF_T
 #define _PTRDIFF_T_
 #define ___int_ptrdiff_t_h
+#define _GCC_PTRDIFF_T
 #ifndef __PTRDIFF_TYPE__
 #define __PTRDIFF_TYPE__ long int
 #endif
 typedef __PTRDIFF_TYPE__ ptrdiff_t;
+#endif /* _GCC_PTRDIFF_T */
 #endif /* ___int_ptrdiff_t_h */
 #endif /* _PTRDIFF_T_ */
 #endif /* __PTRDIFF_T */
 #endif /* _T_PTRDIFF */
+#endif /* _T_PTRDIFF_ */
 #endif /* _PTRDIFF_T */
 
 /* Unsigned type of `sizeof' something.  */
 
 #ifndef _SIZE_T	/* in case <sys/types.h> has defined it. */
+#ifndef _T_SIZE_
 #ifndef _T_SIZE
 #ifndef __SIZE_T
 #ifndef _SIZE_T_
 #ifndef ___int_size_t_h
+#ifndef _GCC_SIZE_T
 #define _SIZE_T
+#define _T_SIZE_
 #define _T_SIZE
 #define __SIZE_T
 #define _SIZE_T_
 #define ___int_size_t_h
+#define _GCC_SIZE_T
 #ifndef __SIZE_TYPE__
 #define __SIZE_TYPE__ long unsigned int
 #endif
 typedef __SIZE_TYPE__ size_t;
+#endif /* _GCC_SIZE_T */
 #endif /* ___int_size_t_h */
 #endif /* _SIZE_T_ */
 #endif /* __SIZE_T */
 #endif /* _T_SIZE */
+#endif /* _T_SIZE_ */
 #endif /* _SIZE_T */
 
 /* Data type for wide chars.  */
@@ -65,12 +77,14 @@ typedef __SIZE_TYPE__ size_t;
 #ifndef __WCHAR_T
 #ifndef _WCHAR_T_
 #ifndef ___int_wchar_t_h
+#ifndef _GCC_WCHAR_T
 #define _WCHAR_T
 #define _T_WCHAR_
 #define _T_WCHAR
 #define __WCHAR_T
 #define _WCHAR_T_
 #define ___int_wchar_t_h
+#define _GCC_WCHAR_T
 #ifndef __WCHAR_TYPE__
 #define __WCHAR_TYPE__ int
 #endif
@@ -81,6 +95,7 @@ typedef __WCHAR_TYPE__ wchar_t;
 #endif
 #endif
 #endif
+#endif
 
 #endif /* __sys_stdtypes_h */