Fixup misc warnings

Patch by RiverRat

http://bugs.gentoo.org/124487

--- a/src/chkshsgr.c
+++ b/src/chkshsgr.c
@@ -1,10 +1,13 @@
 /* Public domain. */
 
+#include <sys/types.h>
+#include <stdlib.h>
+#include <grp.h>
 #include <unistd.h>
 
 int main()
 {
-  short x[4];
+  gid_t x[4];
 
   x[0] = x[1] = 0;
   if (getgroups(1,x) == 0) if (setgroups(1,x) == -1) _exit(1);
--- a/src/matchtest.c
+++ b/src/matchtest.c
@@ -1,3 +1,4 @@
+#include <unistd.h>
 #include "match.h"
 #include "buffer.h"
 #include "str.h"
--- a/src/multilog.c
+++ b/src/multilog.c
@@ -1,3 +1,4 @@
+#include <stdio.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
--- a/src/prot.c
+++ b/src/prot.c
@@ -1,5 +1,8 @@
 /* Public domain. */
 
+#include <sys/types.h>
+#include <unistd.h>
+#include <grp.h>
 #include "hasshsgr.h"
 #include "prot.h"
 
--- a/src/seek_set.c
+++ b/src/seek_set.c
@@ -1,6 +1,7 @@
 /* Public domain. */
 
 #include <sys/types.h>
+#include <unistd.h>
 #include "seek.h"
 
 #define SET 0 /* sigh */
--- a/src/supervise.c
+++ b/src/supervise.c
@@ -1,3 +1,4 @@
+#include <stdio.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
--- a/src/pathexec_run.c
+++ b/src/pathexec_run.c
@@ -1,5 +1,6 @@
 /* Public domain. */
 
+#include <unistd.h>
 #include "error.h"
 #include "stralloc.h"
 #include "str.h"