diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 7eaed917d34..b948d3a90d6 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,8 @@
+2002-05-06  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+	* config/os/irix/irix5.2/bits/os_defines.h (_SGI_SOURCE,
+	__EXTENSIONS__): Ensure they are always defined.
+
 2002-05-06  Phil Edwards  <pme@gcc.gnu.org>
 
 	* docs/html/documentation.html:  Fix broken link.
diff --git a/libstdc++-v3/config/os/irix/irix5.2/bits/os_defines.h b/libstdc++-v3/config/os/irix/irix5.2/bits/os_defines.h
index 1a9eeca68e2..be2d2fbbf30 100644
--- a/libstdc++-v3/config/os/irix/irix5.2/bits/os_defines.h
+++ b/libstdc++-v3/config/os/irix/irix5.2/bits/os_defines.h
@@ -44,6 +44,22 @@
 // the command-line.
 #undef _POSIX_SOURCE
 
+/* On at least irix6.2 (which uses this file,) the header files are
+   very fragile and depend heavily on _SGI_SOURCE and __EXTENSIONS__
+   being defined.  If they're not, then features disappear that
+   configure was relying on which then breaks the libstdc++ headers.
+   These macros are normally implicitly defined by the command-line,
+   however they are not defined when -ansi is used, and -ansi is
+   passed to the testsuite.  The g++ test results (where it uses
+   libstdc++ headers) get dozens of extra failures without these
+   macros, so ensure they always are defined here.  */
+#ifndef _SGI_SOURCE
+# define _SGI_SOURCE
+#endif
+#ifndef __EXTENSIONS__
+# define __EXTENSIONS__
+#endif
+
 #define __off_t off_t
 #define __off64_t off64_t
 #define __ssize_t ssize_t