simplify get_macos_uuid()

also remove a magic number 37 by replacing it with NHUUIDSZ

sys/unix/macuuid.m

@@ -4,7 +4,6 @@
 
 #include "hack.h"
 
-void free_macos_uuid(void);
 void get_macos_uuid(char *);
 
 #ifdef DEBUG
@@ -14,44 +13,22 @@ void get_macos_uuid(char *);
 /* #import <Foundation/Foundation.h> */
 #import <AppKit/AppKit.h>
 
-static const char *macos_uuid = 0;
-
-void
-free_macos_uuid(void)
-{
-    if (macos_uuid) {
-        free((genericptr_t) macos_uuid);
-        macos_uuid = 0;
-    } 
-}
-
 void
 get_macos_uuid(char *target)
 {
     NSString *uuidString = [[NSUUID UUID] UUIDString];
-    const char *str_uuid, *src;
-    char *dst;
+    const char *str_uuid;
     int i;
     
-    if (macos_uuid)
-        free_macos_uuid();
-
     /* str_uuid = [uuidString cStringUsingEncoding:NSUTF8StringEncoding]; */
     str_uuid = [uuidString cStringUsingEncoding:NSASCIIStringEncoding];
-    macos_uuid = dupstr(str_uuid);
     
-    if (macos_uuid) {
-        src = macos_uuid;
-        dst = target;
-        for (i = 0; i < 36; ++i) {
-            *dst = *src;
-            ++src;
-            ++dst;
+    if (str_uuid && target) {
+        for (i = 0; i < (NHUUIDSZ -1 ); ++i) {
+            target[i] = str_uuid[i];
         }
-        dst[36] = '\0';
+        target[(NHUUIDSZ - 1)] = '\0';
     }
-    free_macos_uuid();
-    macos_uuid = 0;
     return;
 }