SDL-1.2: Enable dummy drivers and dlopen in RISC OS builds

From 678fca3749cdd4f808dc8c5d175d7d31a8d5a4ea Mon Sep 17 00:00:00 2001
From: Cameron Cawley <[EMAIL REDACTED]>
Date: Thu, 13 Jan 2022 21:21:52 +0000
Subject: [PATCH] Enable dummy drivers and dlopen in RISC OS builds

---
 README.RISCOS | 2 ++
 configure     | 4 ++++
 configure.ac  | 4 ++++
 3 files changed, 10 insertions(+)

diff --git a/README.RISCOS b/README.RISCOS
index 35ac664e7..ad3ac887d 100644
--- a/README.RISCOS
+++ b/README.RISCOS
@@ -123,6 +123,8 @@ SDL_GetTicks
 SDL_Delay
    Modified to poll keyboard/mouse during the delay on the event thread.
 
+SDL_LoadObject/SDL_LoadFunction/SDL_UnloadObject
+   Not supported in statically linked applications.
 
 Notes on current implementation
 -------------------------------
diff --git a/configure b/configure
index deb44437d..7b531f8ff 100755
--- a/configure
+++ b/configure
@@ -22667,7 +22667,11 @@ case "$host" in
         ;;
     *-riscos)
         ARCH=riscos
+        CheckDummyVideo
+        CheckDiskAudio
+        CheckDummyAudio
         CheckOSS
+        CheckDLOPEN
         CheckPTHREAD
         # Set up files for the video library
         if test x$enable_video = xyes; then
diff --git a/configure.ac b/configure.ac
index 5197de7b6..0c20d5ab3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2974,7 +2974,11 @@ case "$host" in
         ;;
     *-riscos)
         ARCH=riscos
+        CheckDummyVideo
+        CheckDiskAudio
+        CheckDummyAudio
         CheckOSS
+        CheckDLOPEN
         CheckPTHREAD
         # Set up files for the video library
         if test x$enable_video = xyes; then