diff --git a/include/ChangeLog b/include/ChangeLog
index 17cdcd617b8..97aca3775f9 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,9 @@
+2008-07-04  Joel Brobecker  <brobecker@adacore.com>
+
+	* safe-ctype.h: Remove #error when detecting that ctype.h has been
+	included. Redefine the various macros provided by ctype.h as
+	undefined variables.
+
 2008-06-23  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
 	* libiberty.h (XALLOCA, XDUP, XALLOCAVEC, XDUPVEC, XALLOCAVAR,
diff --git a/include/safe-ctype.h b/include/safe-ctype.h
index e59b357ccfb..b3e911e07bd 100644
--- a/include/safe-ctype.h
+++ b/include/safe-ctype.h
@@ -35,10 +35,6 @@ Boston, MA 02110-1301, USA.  */
 #ifndef SAFE_CTYPE_H
 #define SAFE_CTYPE_H
 
-#ifdef isalpha
- #error "safe-ctype.h and ctype.h may not be used simultaneously"
-#endif
-
 /* Determine host character set.  */
 #define HOST_CHARSET_UNKNOWN 0
 #define HOST_CHARSET_ASCII   1
@@ -116,4 +112,36 @@ extern const unsigned char  _sch_tolower[256];
 #define TOUPPER(c) _sch_toupper[(c) & 0xff]
 #define TOLOWER(c) _sch_tolower[(c) & 0xff]
 
+/* Prevent the users of safe-ctype.h from accidently using the routines
+   from ctype.h.  Initially, the approach was to produce an error when
+   detecting that ctype.h has been included.  But this was causing
+   trouble as ctype.h might get indirectly included as a result of
+   including another system header (for instance gnulib's stdint.h).  */
+#undef isalpha
+#define isalpha(c) do_not_use_isalpha_with_safe_ctype
+#undef isalnum
+#define isalnum(c) do_not_use_isalnum_with_safe_ctype
+#undef iscntrl
+#define iscntrl(c) do_not_use_iscntrl_with_safe_ctype
+#undef isdigit
+#define isdigit(c) do_not_use_isdigit_with_safe_ctype
+#undef isgraph
+#define isgraph(c) do_not_use_isgraph_with_safe_ctype
+#undef islower
+#define islower(c) do_not_use_islower_with_safe_ctype
+#undef isprint
+#define isprint(c) do_not_use_isprint_with_safe_ctype
+#undef ispunct
+#define ispunct(c) do_not_use_ispunct_with_safe_ctype
+#undef isspace
+#define isspace(c) do_not_use_isspace_with_safe_ctype
+#undef isupper
+#define isupper(c) do_not_use_isupper_with_safe_ctype
+#undef isxdigit
+#define isxdigit(c) do_not_use_isxdigit_with_safe_ctype
+#undef toupper
+#define toupper(c) do_not_use_toupper_with_safe_ctype
+#undef tolower
+#define tolower(c) do_not_use_tolower_with_safe_ctype
+
 #endif /* SAFE_CTYPE_H */