Fix most of m32r libgloss for c99/gcc-14

Make implicit its explicit, add missing prototypes and header includes.  This
does not fix m32r-stub.c which needs more than the trivial work that Jeff J has
pre-approved.

libgloss/m32r/exit.c

@@ -4,7 +4,7 @@
 #include "eit.h"
 
 void
-_exit (n)
+_exit (int n)
 {
   TRAP0 (SYS_exit, n, 0, 0);
 }

libgloss/m32r/kill.c

@@ -3,7 +3,8 @@
 #include "syscall.h"
 #include "eit.h"
 
-_kill (n, m)
+int
+_kill (int n, int m)
 {
   return TRAP0 (SYS_exit, 0xdead, 0, 0);
 }

libgloss/m32r/raise.c

@@ -1,5 +1,6 @@
 /* ??? Needed?  */
 
-_raise ()
+int
+_raise (void)
 {
 }

libgloss/m32r/sbrk.c

@@ -2,6 +2,10 @@
 #include <sys/stat.h>
 #include "syscall.h"
 #include "eit.h"
+#include <stdlib.h>
+
+
+extern int _write (int, char *, int);
 
 caddr_t
 _sbrk (int incr)