Compiler warning under cygwin/mingw (was: fix for 50a6c8e)

That compiles OK, thanks.

Sorry for high-jacking this thread, but while compiling under CYGWIN, found one warning:

    LINK git-credential-store.exe
     CC daemon.o
daemon.c: In function ‘drop_privileges’:
daemon.c:1136:15: warning: implicit declaration of function ‘initgroups’ 
[-Wimplicit-function-declaration]
   if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
                ^

t9115 doesn't pass, NTFS doesn't like the non-UTF filenames, it seams. Probably the same problem as under Mac OS /HFS+- -----------------------

And MINGW is not happy for other reasons:

builtin/rev-parse.c: In function 'cmd_rev_parse':
builtin/rev-parse.c:775:12: warning: implicit declaration of function 
'realpath' [-Wimplicit-function-declaration]
        if (!realpath(gitdir, absolute_path))
             ^
     CC builtin/revert.o

     CC builtin/write-tree.o
     LINK git.exe
builtin/rev-parse.o: In function `cmd_rev_parse':
C:\Users\tb\projects\git\tb/builtin/rev-parse.c:775: undefined reference to 
`realpath'
collect2.exe: error: ld returned 1 exit status
Makefile:1725: recipe for target 'git.exe' failed
make: *** [git.exe] Error 1