SDL: storage: generic title storage allows override paths without '/' appended.

SDL Commits
1 
From 3ffb1a8cbdf3b986965b51c16c540f4e6d793010 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Wed, 15 Jan 2025 23:47:43 -0500
Subject: [PATCH] storage: generic title storage allows override paths without
 '/' appended.

Fixes #11299.
---
 src/storage/generic/SDL_genericstorage.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/storage/generic/SDL_genericstorage.c b/src/storage/generic/SDL_genericstorage.c
index 3d3e93025b1cc..b1270a761bab2 100644
--- a/src/storage/generic/SDL_genericstorage.c
+++ b/src/storage/generic/SDL_genericstorage.c
@@ -236,10 +236,15 @@ static const SDL_StorageInterface GENERIC_title_iface = {
 static SDL_Storage *GENERIC_Title_Create(const char *override, SDL_PropertiesID props)
 {
     SDL_Storage *result = NULL;
-
     char *basepath = NULL;
+
     if (override != NULL) {
-        basepath = SDL_strdup(override);
+        // make sure override has a path separator at the end. If you're not on Windows and used '\\', that's on you.
+        const size_t slen = SDL_strlen(override);
+        const bool need_sep = (!slen || ((override[slen-1] != '/') && (override[slen-1] != '\\')));
+        if (SDL_asprintf(&basepath, "%s%s", override, need_sep ? "/" : "") == -1) {
+            return NULL;
+        }
     } else {
         const char *base = SDL_GetBasePath();
         basepath = base ? SDL_strdup(base) : NULL;