[tex-live] 64 bits version of TeX Live on Windows

[Karl Berry]

    ../../../texk/web2c/pdftexdir/regex/regex_internal.h:424:0: warning:
    "alloca" redefined
     # define alloca(size)   __builtin_alloca (size)

I will add the obvious #ifndef in regex_internal.h to avoid the warning.  -k