From 2c2a73e320375bb15f23996d4d6bc143ba176627 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Sat, 6 Feb 2021 17:07:21 -0600
Subject: [PATCH] Fix build and require SDL 2.0.15 to hook

---
 app/app.pro      |  1 +
 app/masterhook.c | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/app/app.pro b/app/app.pro
index a710e9c8..a91c4fd2 100644
--- a/app/app.pro
+++ b/app/app.pro
@@ -254,6 +254,7 @@ libdrm {
     linux {
         message(Master hooks enabled)
         SOURCES += masterhook.c
+        LIBS += -ldl
     }
 }
 config_EGL {
diff --git a/app/masterhook.c b/app/masterhook.c
index 0c4b4b92..e7e6b84a 100644
--- a/app/masterhook.c
+++ b/app/masterhook.c
@@ -20,6 +20,14 @@
 #include <xf86drm.h>
 #include <xf86drmMode.h>
 
+// We require SDL 2.0.15+ to hook because it supports sharing
+// the DRM FD with our code. This avoids having multiple DRM FDs
+// in flight at the same time which would significantly complicate
+// the logic here because we'd need to figure out exactly which FD
+// should be the master at any given time. With the position of our
+// hooks, that is definitely not trivial.
+#if SDL_VERSION_ATLEAST(2, 0, 15)
+
 // Qt's DRM master FD grabbed by our hook
 int g_QtDrmMasterFd = -1;
 struct stat64 g_DrmMasterStat;
@@ -134,3 +142,5 @@ int close(int fd)
     }
     return ret;
 }
+
+#endif