StdLib: Improve robustness of stat() and make basename() a public function.

AppPkg: Refinements to pyconfig.h and port of getpath.c to EDK II.

Signed-off-by: darylm503
Reviewed-by: geekboy15a
Reviewed-by: jljusten


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12508 6f19259b-4bc3-4df7-8a09-765794883524

StdLib/Include/unistd.h

@@ -39,6 +39,7 @@ pid_t           tcgetpgrp(int);
 char           *getpass(const char *);
 int             usleep(useconds_t);
 unsigned int    sleep(unsigned int);
+char           *basename(char *path);
 
 // Networking
 long            gethostid(void);