SDL: pulseaudio: Added typedef needed for compat with ancient Pulse installs.

From a2c5dc65076678171eab2480cea3ea2624ad1f8d Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Thu, 28 Sep 2023 12:10:16 -0400
Subject: [PATCH] pulseaudio: Added typedef needed for compat with ancient
 Pulse installs.

---
 src/audio/pulseaudio/SDL_pulseaudio.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/audio/pulseaudio/SDL_pulseaudio.c b/src/audio/pulseaudio/SDL_pulseaudio.c
index a6333bf4930f..7de23b065df7 100644
--- a/src/audio/pulseaudio/SDL_pulseaudio.c
+++ b/src/audio/pulseaudio/SDL_pulseaudio.c
@@ -35,6 +35,10 @@
 #include "SDL_pulseaudio.h"
 #include "../../thread/SDL_systhread.h"
 
+#if (PA_PROTOCOL_VERSION < 28)
+typedef void (*pa_operation_notify_cb_t) (pa_operation *o, void *userdata);
+#endif
+
 /* should we include monitors in the device list? Set at SDL_Init time */
 static SDL_bool include_monitors = SDL_FALSE;