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
diff --git a/coreutils/date.c b/coreutils/date.c
index 73fc705..8b6a062 100644
--- a/coreutils/date.c
+++ b/coreutils/date.c
@@ -31,6 +31,7 @@
 #include <unistd.h>
 #include <time.h>
 #include <stdio.h>
+#include <string.h>
 #include <getopt.h>