Cygwin: globals: make __progname an alias of program_invocation_short_name
On Linux, __progname and program_invocation_short_name are just
different exported names of the same string. Do the same in Cygwin.
This requires to tweak the mkglobals_h so as not to touch the
EXPORT_ALIAS expression. Also, use the base variable
program_invocation_short_name throughout. __progname is just
the export for getopt.
git://sourceware.org / newlib-cygwin.git / commit