warning message tweak

[Bruno Haible]

This clarifies that the messages are warnings, not errors.

2007-02-04  Bruno Haible  <address@hidden>

        * lib/string_.h (GL_LINK_WARNING2): Put the word "warning:" into the
        warning message.

--- lib/string_.h       5 Feb 2007 03:34:24 -0000       1.17
+++ lib/string_.h       5 Feb 2007 03:37:00 -0000
@@ -37,7 +37,7 @@
 #  define GL_LINK_WARNING1(file, line, message) \
      GL_LINK_WARNING2 (file, line, message)  /* macroexpand file and line */
 #  define GL_LINK_WARNING2(file, line, message) \
-     GL_LINK_WARNING3 (file ":" #line ": " message)
+     GL_LINK_WARNING3 (file ":" #line ": warning: " message)
 #  define GL_LINK_WARNING3(message) \
      ({ static const char warning[sizeof (message)]            \
           __attribute__ ((__unused__,                          \