sdl12-compat: Fixed a call to SDL_SetError that should be SDL20_SetError

SDL Commits
1 
From ceee6cd0643aa58a867b8639df6ed0c2255dde6e Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Thu, 24 Jun 2021 15:26:53 -0400
Subject: [PATCH] Fixed a call to SDL_SetError that should be SDL20_SetError

---
 src/SDL12_compat.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/SDL12_compat.c b/src/SDL12_compat.c
index 8d25fb7..753cddf 100644
--- a/src/SDL12_compat.c
+++ b/src/SDL12_compat.c
@@ -6428,7 +6428,7 @@ ValidCDDriveIndex(const int drive)
     }
 
     if (!CDRomPath || (drive != 0)) {
-        SDL_SetError("Invalid CD-ROM drive index");
+        SDL20_SetError("Invalid CD-ROM drive index");
         return SDL_FALSE;
     }