PATCH (3.3): -Wall -Wsystem-headers nits; preemptive check on one system

Tue Apr 15 06:24:00 GMT 2003

And, back port this test case to 3.3 since we did regress; a past
release was -Wsystem-headers clean for OSes that had clean C headers.

        * include/bits/concept_check.h: Fix multi-line comment.
        * testsuite/17_intro/headers.cc (dg-options): Add -Wall -Wsystem-header
        when target is *-*-freebsd*.

[cvs update -j1.5 -j1.6 include/bits/concept_check.h
 cvs update -j1.3 -j1.4 testsuite/17_intro/headers.cc]