Some sed implementations are not greedy enough, use perl instead

The issue is demonstrated as follows:

  On Linux:

    $ echo ': foo.h /usr/include/stddef.h bar.h' | sed -e 's/ \/\(\\.\|[^ ]\)*//g'
    : foo.h bar.h

  On MacOS X:

    $ echo ': foo.h /usr/include/stddef.h bar.h' | sed -e 's/ \/\(\\.\|[^ ]\)*//g'
    : foo.husr/include/stddef.h bar.h

Perl is more consistent:

  On Linux:

    $ echo ': foo.h /usr/include/stddef.h bar.h' | perl -pe 's/ \/(\\.|[^ ])*//g;'
    : foo.h bar.h

  On MacOS X:

    $ echo ': foo.h /usr/include/stddef.h bar.h' | perl -pe 's/ \/(\\.|[^ ])*//g;'
    : foo.h bar.h

Reviewed-by: Andy Polyakov <appro@openssl.org>