made #undef isdigit for everybody, instead of just MSVC.

(got the same macro on Mdk9 g++-3.2, for whatever reason)


[SVN r17172]

libs/format

@@ -1 +1 @@
-Subproject commit 5c63f2e1486771346f1c10981a61c6e43bd080a4
+Subproject commit 4c88b8ee50d027c6c5e24dddf4445eec22f35c66