Pull up following revision(s) (requested by kamil in ticket #768):

external/gpl2/gmake/dist/glob/glob.c: revision 1.4

According to:
    https://sourceforge.net/p/predef/wiki/Libraries/

The macro used for old glibc is __GNU_LIBRARY__ and the new one is
__GLIBC__.

Try to fix linux compilation by detecting both.

(martin)