Fixed problem with Unix version of _fullpath - can't use cwd if chdir failed.

src/sbbs3/wrappers.c

@@ -296,9 +296,12 @@ char* _fullpath(char* absPath, const char* relPath, size_t maxLength)
 	}
 
     getcwd(curdir, PATH_MAX);
-    chdir(relPath);
+    if(chdir(relPath)!=0) /* error, invalid dir */
+		strcpy(absPath,relPath);
+	else {
 		getcwd(absPath, maxLength);
 		chdir(curdir);
+	}
 	free(curdir);
 
     return absPath;