exclude AC_PROG_CXX_C_O from one test, for Solaris+g++

[Paul Eggert]

I installed this to prevent an Autoconf test failure in the
all-too-common case where g++ generates non-working executables on
Solaris:

2006-11-09  Paul Eggert  <address@hidden>

        * tests/mktests.sh (ac_exclude_list): Exclude AC_PROG_CXX_C_O, for
        benefit of platforms like Solaris+GCC where it is common to have a
        non-working g++ installation.

--- tests/mktests.sh.~1.56.~    2006-09-01 22:37:08.000000000 -0700
+++ tests/mktests.sh    2006-11-08 23:48:49.000000000 -0800
@@ -131,6 +131,9 @@ ac_exclude_list='
        /^AC_(PROG_CC|C_CONST|C_VOLATILE)$/ {next}
        /^AC_PATH_XTRA$/ {next}
 
+       # Requires a working C++ compiler, which is not a given.
+       /^AC_PROG_CXX_C_O$/ {next}
+
        # Already tested by AT_CHECK_MACRO.
        /^AC_OUTPUT$/ {next}
 '