Maelstrom: Use the disabled color for default button borders when they're disabled.

https://github.com/libsdl-org/Maelstrom/commit/4007b49276761de2cb22717f105daf51cf49fc87

From 4007b49276761de2cb22717f105daf51cf49fc87 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Sun, 6 Nov 2011 00:03:57 -0400
Subject: [PATCH] Use the disabled color for default button borders when
 they're disabled.

---
 MacDialog.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/MacDialog.cpp b/MacDialog.cpp
index 0c014161..045ee53c 100644
--- a/MacDialog.cpp
+++ b/MacDialog.cpp
@@ -205,7 +205,11 @@ MacDialogButton::OnDraw()
 		maxy = y+4+m_element->Height()+4-1;
 
 		// The edge always uses the real foreground color
-		color = m_colors[1];
+		if (m_element->IsDisabled()) {
+			color = m_element->GetDisabledColor();
+		} else {
+			color = m_colors[1];
+		}
 
 		m_screen->DrawLine(x+5, y, maxx-5, y, color);
 		m_screen->DrawLine(x+3, y+1, maxx-3, y+1, color);