sdl12-compat: Implement OS_GetExeName for macOS and FreeBSD

SDL Commits
1 
From f4e2d1a30a6df8fef72c283af466c6aa21ec1280 Mon Sep 17 00:00:00 2001
From: Joshua Root <[EMAIL REDACTED]>
Date: Sat, 17 Sep 2022 11:08:07 +1000
Subject: [PATCH] Implement OS_GetExeName for macOS and FreeBSD

---
 src/SDL12_compat.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/SDL12_compat.c b/src/SDL12_compat.c
index 2dddc1693..ddfd57943 100644
--- a/src/SDL12_compat.c
+++ b/src/SDL12_compat.c
@@ -1223,6 +1223,15 @@ static void OS_GetExeName(char *buf, const unsigned maxpath) {
     buf[0] = '\0';
     DosQueryModuleName(pib->pib_hmte, maxpath, buf);
 }
+#elif defined(__APPLE__) || defined(__FREEBSD__)
+static void OS_GetExeName(char *buf, const unsigned maxpath) {
+    const char *progname = getprogname();
+    if (progname != NULL) {
+        strlcpy(buf, progname, maxpath);
+    } else {
+        buf[0] = '\0';
+    }
+}
 #else
 #warning Please implement this for your platform.
 static void OS_GetExeName(char *buf, const unsigned maxpath) {