-g3 is definitively not a standard gcc option, at least not on anything

else than a quite recent version. Using this option prevent gdb from accessing
the contents of some of the structures. The error message is:
Unexpected type (0) encountered for integer constant.

This commit was SVN r9994.

config/ompi_setup_cc.m4

@@ -49,7 +49,7 @@ AC_DEFUN([OMPI_SETUP_CC],[
     # Do we want debugging?
     if test "$WANT_DEBUG" = "1" -a "$enable_debug_symbols" != "no" ; then
         if test "$ompi_c_vendor" = "gnu"; then
-            CFLAGS="$CFLAGS -g3"
+            CFLAGS="$CFLAGS -g"  # keep the -g3 for when it will become a standard option.
         else
             CFLAGS="$CFLAGS -g"
         fi