`extern char **environ;` is not always harmless
SwissTorExit reports a compile error on Kubuntu 11.10 amd64, with GCC 4.6.1:
compat.c:1667:15: erreur: redundant redeclaration of ‘environ’ [-Werror=redundant-decls]
/usr/include/unistd.h:542:15: note: previous declaration of ‘environ’ was here
cc1: all warnings being treated as errors
Apparently extern char **environ;
isn't always harmless.