[boost] patch: Boost.Jam: PATH_MAX not defined in SCO 5.0.5

Added default for PATH_MAX as it isn't defined on my system (sco3.2v5.0.5/gcc2.95.2) --- tools/build/jam_src/pwd.c.orig 2004-12-13 14:58:32.362510600 -0500 +++ tools/build/jam_src/pwd.c 2004-12-12 17:32:07.000000000 -0500 @@ -21,7 +21,9 @@ #endif #endif - +#ifndef PATH_MAX +# define PATH_MAX 4096 +#endif LIST* pwd(void)