sdl12-compat: SDL12_compat_objc.m: make it build against older SDKs

From d1d154db98aeccfcd5746d53111380a5410f1eac Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Tue, 1 Jun 2021 14:55:50 +0300
Subject: [PATCH] SDL12_compat_objc.m: make it build against older SDKs

Fixes: https://github.com/libsdl-org/sdl12-compat/issues/77
---
 src/SDL12_compat_objc.m | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/SDL12_compat_objc.m b/src/SDL12_compat_objc.m
index a00e0b4..5c90314 100644
--- a/src/SDL12_compat_objc.m
+++ b/src/SDL12_compat_objc.m
@@ -43,6 +43,10 @@ SDL12_PRIVATE void sdl12_compat_macos_init(void)
     [NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
 }
 
+#ifndef MAC_OS_X_VERSION_10_12
+#define NSAlertStyleCritical NSCriticalAlertStyle
+#endif
+
 SDL12_PRIVATE void error_dialog(const char *errorMsg)
 {
     if (NSApp == nil) {