Use more portable random seed generation.

The new function md_random_seed() has replaced time() + getpid() and
similar methods.  Putting everything in mdport.c slightly reduces the
warnings and workarounds.

rogue4/extern.h

@@ -93,3 +93,4 @@ extern int   md_shellescape(void);
 extern void  md_sleep(int s);
 extern int   md_unlink(char *file);
 extern int   md_unlink_open_file(char *file, int inf);
+extern unsigned int md_random_seed(void);

rogue4/main.c

@@ -29,7 +29,6 @@ int
 main(int argc, char *argv[], char *envp[])
 {
     register char *env;
-    int lowtime;
 
     md_init();
 
@@ -138,8 +137,6 @@ main(int argc, char *argv[], char *envp[])
     if (!use_savedir)
         md_normaluser();
 
-    lowtime = (int) time(NULL);
-
 #ifdef WIZARD
     noscore = wizard;
 #endif
@@ -149,7 +146,7 @@ main(int argc, char *argv[], char *envp[])
 	noscore = TRUE;
     }
     else
-	dnum = lowtime + getpid();
+	dnum = md_random_seed();
 #ifdef WIZARD
     if (wizard)
 	printf("Hello %s, welcome to dungeon #%d", whoami, dnum);

rogue4/mdport.c

@@ -82,6 +82,7 @@ char *strdup(const char *s);
 #include <limits.h>
 #include <sys/stat.h>
 #include <signal.h>
+#include <time.h>
 
 #define MOD_MOVE(c) (toupper(c) )
 
@@ -1313,3 +1314,16 @@ md_readchar(WINDOW *win)
 
     return(ch & 0x7F);
 }
+
+unsigned int
+md_random_seed(void)
+{
+    unsigned int seed;
+    seed = (unsigned int) time((time_t *) NULL);
+#ifdef _WIN32
+    seed += _getpid();
+#else
+    seed += getpid();
+#endif
+    return seed;
+}

rogue4/new_level.c

@@ -73,7 +73,7 @@ new_level(void)
 	if (i++ > 100)
 	{
 	    i = 0;
-	    srand(getpid() + (int) time((time_t *) NULL));
+	    srand(md_random_seed());
 	}
     } until (_level[index] == FLOOR);
     _level[index] = STAIRS;

rogue4/save.c

@@ -317,7 +317,7 @@ restore(char *file, char **envp)
     setup();
     clearok(curscr, TRUE);
     touchwin(stdscr);
-    srand(getpid());
+    srand(md_random_seed());
     msg("file name: %s", file);
 	status();
     playit();