Avoid compiler casting warnings Part 2

This saves instructions that are related to casting as well as compiler warnings.

lib/util/mktemp.c

@@ -90,7 +90,7 @@ mktemp_internal(int dfd, char *path, int slen, int mode, int flags)
 		cp = start;
 		do {
 			unsigned short rbuf[16];
-			unsigned int i;
+			size_t i;
 
 			/*
 			 * Avoid lots of arc4random() calls by using

lib/util/regress/tailq/hltq_test.c

@@ -201,5 +201,5 @@ main(int argc, char *argv[])
 	    getprogname(), ntests, errors, (ntests - errors) * 100 / ntests);
     }
 
-    exit(errors);
+    return errors;
 }

lib/util/sudo_debug.c

@@ -304,7 +304,8 @@ sudo_debug_register_v2(const char *program, const char *const subsystems[],
     }
 
     if (instance == NULL) {
-	unsigned int i, j, max_id = NUM_DEF_SUBSYSTEMS - 1;
+	size_t i;
+	unsigned int j, max_id = NUM_DEF_SUBSYSTEMS - 1;
 
 	/* Fill in subsystem name -> id mapping as needed. */
 	if (ids != NULL) {
@@ -348,7 +349,7 @@ sudo_debug_register_v2(const char *program, const char *const subsystems[],
     } else {
 	/* Check for matching instance but different ids[]. */
 	if (ids != NULL && instance->subsystem_ids != ids) {
-	    unsigned int i;
+	    size_t i;
 
 	    for (i = 0; subsystems[i] != NULL; i++)
 		ids[i] = instance->subsystem_ids[i];

lib/util/ttyname_dev.c

@@ -121,7 +121,7 @@ sudo_ttyname_scan(const char *dir, dev_t rdev, char *name, size_t namelen)
     char *ret = NULL;
     struct dirent *dp;
     struct stat sb;
-    unsigned int i;
+    size_t i;
     DIR *d = NULL;
     debug_decl(sudo_ttyname_scan, SUDO_DEBUG_UTIL);