(svn r27886) -Fix [FS#6575-ish]: Do not modify argv[0].

src/fileio.cpp

@@ -1032,30 +1032,29 @@ extern void DetermineBasePaths(const char *exe);
  */
 static bool ChangeWorkingDirectoryToExecutable(const char *exe)
 {
+	char tmp[MAX_PATH];
+	strecpy(tmp, exe, lastof(tmp));
+
 	bool success = false;
 #ifdef WITH_COCOA
-	char *app_bundle = strchr(exe, '.');
+	char *app_bundle = strchr(tmp, '.');
 	while (app_bundle != NULL && strncasecmp(app_bundle, ".app", 4) != 0) app_bundle = strchr(&app_bundle[1], '.');
 
-	if (app_bundle != NULL) app_bundle[0] = '\0';
+	if (app_bundle != NULL) *app_bundle = '\0';
 #endif /* WITH_COCOA */
-	char *s = const_cast<char *>(strrchr(exe, PATHSEPCHAR));
+	char *s = strrchr(tmp, PATHSEPCHAR);
 	if (s != NULL) {
 		*s = '\0';
 #if defined(__DJGPP__)
 		/* If we want to go to the root, we can't use cd C:, but we must use '/' */
-		if (s[-1] == ':') chdir("/");
+		if (s > tmp && *(s - 1) == ':') chdir("/");
 #endif
-		if (chdir(exe) != 0) {
+		if (chdir(tmp) != 0) {
 			DEBUG(misc, 0, "Directory with the binary does not exist?");
 		} else {
 			success = true;
 		}
-		*s = PATHSEPCHAR;
 	}
-#ifdef WITH_COCOA
-	if (app_bundle != NULL) app_bundle[0] = '.';
-#endif /* WITH_COCOA */
 	return success;
 }