-current breaking (some?) ports, how to detect which?

[Anton Shterenlikht]

>From Jan Beich (gecko@):

*quote*
> In file included from /usr/include/sys/stat.h:99:0,
>                  from /usr/local/include/fontconfig/fontconfig.h:29,
>                  from configure:25673:
> /usr/include/sys/time.h:134:17: error: unknown type name 'sbintime_t'
> /usr/include/sys/time.h:141:1: error: unknown type name 'sbintime_t'
> /usr/include/sys/time.h: In function 'bttosbt':
> /usr/include/sys/time.h:144:12: error: 'sbintime_t' undeclared (first use in this function)
> /usr/include/sys/time.h:144:12: note: each undeclared identifier is reported only once for each function it appears in
> /usr/include/sys/time.h:144:23: error: expected ')' before 'bt'
> /usr/include/sys/time.h: At top level:
> /usr/include/sys/time.h:148:9: error: unknown type name 'sbintime_t'
> /usr/include/sys/time.h:206:9: error: unknown type name 'sbintime_t'
> /usr/include/sys/time.h:216:1: error: unknown type name 'sbintime_t'
> /usr/include/sys/time.h: In function 'tstosbt':
> /usr/include/sys/time.h:219:12: error: 'sbintime_t' undeclared (first use in this function)
> /usr/include/sys/time.h:219:23: error: expected ')' before 'ts'
> /usr/include/sys/time.h: At top level:
> /usr/include/sys/time.h:224:9: error: unknown type name 'sbintime_t'
> /usr/include/sys/time.h:234:1: error: unknown type name 'sbintime_t'
> /usr/include/sys/time.h: In function 'tvtosbt':
> /usr/include/sys/time.h:237:12: error: 'sbintime_t' undeclared (first use in this function)
> /usr/include/sys/time.h:237:23: error: expected ')' before 'tv'

This is common error when headers modified by gcc are not in sync
with those under /usr/include. For example, after

http://svnweb.freebsd.org/changeset/base/247476

make sure you have sbintime_t in sys/types.h copy

  $ fgrep sbintime /usr/local/lib/gcc47/gcc/x86_64-portbld-freebsd10.0/4.7.3/include-fixed/sys/types.h
  typedef __int64_t       sbintime_t;

If you don't have then rebuild lang/gcc47.

*end quote*

So I'm rebuilding gcc47 now, but
how do I know that other ports are unaffected?
Or how do I find which other ports are affected? 

Is this something that current@ should communicate
to ports@ more explicitly?
Is this something that should be noted in ports/UPDATING?

Thanks

Anton