Merge branch 'js/test-ln-s-add'

Many tests that check the behaviour of symbolic links stored in the
index or the tree objects do not have to be skipped on a filesystem
that lack symbolic link support.

* js/test-ln-s-add:
  t4011: remove SYMLINKS prerequisite
  t6035: use test_ln_s_add to remove SYMLINKS prerequisite
  t3509, t4023, t4114: use test_ln_s_add to remove SYMLINKS prerequisite
  t3100: use test_ln_s_add to remove SYMLINKS prerequisite
  t3030: use test_ln_s_add to remove SYMLINKS prerequisite
  t0000: use test_ln_s_add to remove SYMLINKS prerequisite
  tests: use test_ln_s_add to remove SYMLINKS prerequisite (trivial cases)
  tests: introduce test_ln_s_add
  t3010: modernize style
  test-chmtime: Fix exit code on Windows

test-chmtime.c

@@ -84,7 +84,7 @@ int main(int argc, char *argv[])
 		if (stat(argv[i], &sb) < 0) {
 			fprintf(stderr, "Failed to stat %s: %s\n",
 			        argv[i], strerror(errno));
-			return -1;
+			return 1;
 		}
 
 #ifdef GIT_WINDOWS_NATIVE
@@ -92,7 +92,7 @@ int main(int argc, char *argv[])
 				chmod(argv[i], sb.st_mode | S_IWUSR)) {
 			fprintf(stderr, "Could not make user-writable %s: %s",
 				argv[i], strerror(errno));
-			return -1;
+			return 1;
 		}
 #endif
 
@@ -107,7 +107,7 @@ int main(int argc, char *argv[])
 		if (utb.modtime != sb.st_mtime && utime(argv[i], &utb) < 0) {
 			fprintf(stderr, "Failed to modify time on %s: %s\n",
 			        argv[i], strerror(errno));
-			return -1;
+			return 1;
 		}
 	}
 
@@ -115,5 +115,5 @@ int main(int argc, char *argv[])
 
 usage:
 	fprintf(stderr, "usage: %s %s\n", argv[0], usage_str);
-	return -1;
+	return 1;
 }