gnulib: install the environ module
This should fix compilation on OSX, as reported by Yann Thierry-Mieg.
- m4/environ.m4: New file.
- m4/gnulib-cache.m4, m4/gnulib-comp.m4: Update.
- bin/common_trans.cc [HAVE_SPAWN_H]: Do not define environ.
This should fix compilation on OSX, as reported by Yann Thierry-Mieg.