Fix header file usage -- there were many unnecessary header files included in

busybox.h which slowed compiles.  I left only what was needed and then fixed up
all the apps to include their own header files.  I also fixed naming for pwd.h
and grp.h functions.  Tested to compile and run with libc5, glibc, and uClibc.
 -Erik

coreutils/uudecode.c

@@ -27,6 +27,10 @@
 #include <stdio.h>
 #include <errno.h>
 #include <getopt.h>
+#include <string.h>
+#include <stdlib.h>
+#include "pwd_grp/pwd.h"
+#include "pwd_grp/grp.h"
 
 /*struct passwd *getpwnam();*/