Disable the offscreen video driver if EGL is unavailable (#6234)

CMakeLists.txt

@@ -1177,13 +1177,6 @@ if(SDL_VIDEO)
     set(HAVE_DUMMYVIDEO TRUE)
     set(HAVE_SDL_VIDEO TRUE)
   endif()
-  if(SDL_OFFSCREEN)
-    set(SDL_VIDEO_DRIVER_OFFSCREEN 1)
-    file(GLOB VIDEO_OFFSCREEN_SOURCES ${SDL3_SOURCE_DIR}/src/video/offscreen/*.c)
-    list(APPEND SOURCE_FILES ${VIDEO_OFFSCREEN_SOURCES})
-    set(HAVE_OFFSCREEN TRUE)
-    set(HAVE_SDL_VIDEO TRUE)
-  endif()
 endif()
 
 # Platform-specific options and settings
@@ -2748,6 +2741,16 @@ endif()
 # Platform-independent options
 CheckLibSampleRate()
 
+if(SDL_VIDEO)
+  if(SDL_OFFSCREEN AND SDL_VIDEO_OPENGL_EGL)
+    set(SDL_VIDEO_DRIVER_OFFSCREEN 1)
+    file(GLOB VIDEO_OFFSCREEN_SOURCES ${SDL3_SOURCE_DIR}/src/video/offscreen/*.c)
+    list(APPEND SOURCE_FILES ${VIDEO_OFFSCREEN_SOURCES})
+    set(HAVE_OFFSCREEN TRUE)
+    set(HAVE_SDL_VIDEO TRUE)
+  endif()
+endif()
+
 # Dummies
 # configure.ac does it differently:
 # if not have X

configure.ac

@@ -2177,7 +2177,11 @@ CheckOffscreenVideo()
     AC_ARG_ENABLE(video-offscreen,
 [AS_HELP_STRING([--enable-video-offscreen], [use offscreen video driver [default=yes]])],
                   , enable_video_offscreen=yes)
-    if test x$enable_video_offscreen = xyes; then
+
+    if  test x$enable_video = xyes && \
+        test x$enable_video_offscreen = xyes && \
+        test x$video_opengl_egl = xyes; then
+
         AC_DEFINE(SDL_VIDEO_DRIVER_OFFSCREEN, 1, [ ])
         SOURCES="$SOURCES $srcdir/src/video/offscreen/*.c"
         have_video=yes
@@ -3470,7 +3474,6 @@ case "$host" in
         CheckWerror
         CheckDeclarationAfterStatement
         CheckDummyVideo
-        CheckOffscreenVideo
         CheckDiskAudio
         CheckDummyAudio
         CheckDLOPEN
@@ -3487,8 +3490,9 @@ case "$host" in
         # Need to check for Raspberry PI first and add platform specific compiler flags, otherwise the test for GLES fails!
         CheckRPI
         CheckX11
-        # Need to check for EGL first because KMSDRM and Wayland depends on it.
+        # Need to check for EGL first because Offscreen, KMSDRM and Wayland depend on it.
         CheckEGL
+        CheckOffscreenVideo
         CheckKMSDRM
         CheckGLX
         CheckOpenGL
@@ -3686,12 +3690,12 @@ case "$host" in
         CheckWerror
         CheckDeclarationAfterStatement
         CheckDummyVideo
-        CheckOffscreenVideo
         CheckDiskAudio
         CheckDummyAudio
         CheckWINDOWS
         CheckWINDOWSGL
         CheckWINDOWSGLES
+        CheckOffscreenVideo
         CheckVulkan
         CheckDIRECTX
         CheckHIDAPI
@@ -3847,7 +3851,6 @@ dnl BeOS support removed after SDL 2.0.1. Haiku still works.  --ryan.
         ARCH=haiku
         ac_default_prefix=/boot/system
         CheckDummyVideo
-        CheckOffscreenVideo
         CheckDiskAudio
         CheckDummyAudio
         CheckDLOPEN
@@ -3909,7 +3912,6 @@ dnl BeOS support removed after SDL 2.0.1. Haiku still works.  --ryan.
         CheckNoErrorDeprecatedDeclarationsWerror
         CheckDeclarationAfterStatement
         CheckDummyVideo
-        CheckOffscreenVideo
         CheckDiskAudio
         CheckDummyAudio
         CheckDLOPEN
@@ -4026,7 +4028,6 @@ dnl BeOS support removed after SDL 2.0.1. Haiku still works.  --ryan.
         CheckNoErrorDeprecatedDeclarationsWerror
         CheckDeclarationAfterStatement
         CheckDummyVideo
-        CheckOffscreenVideo
         CheckDiskAudio
         CheckDummyAudio
         CheckDLOPEN
@@ -4038,6 +4039,7 @@ dnl BeOS support removed after SDL 2.0.1. Haiku still works.  --ryan.
         CheckMacGLES
         CheckGLX
         CheckOpenGL
+        CheckOffscreenVideo
         CheckVulkan
         CheckPTHREAD
         CheckHIDAPI
@@ -4129,13 +4131,13 @@ dnl BeOS support removed after SDL 2.0.1. Haiku still works.  --ryan.
         CheckWerror
         CheckDeclarationAfterStatement
         CheckDummyVideo
-        CheckOffscreenVideo
         CheckDiskAudio
         CheckDummyAudio
         CheckPTHREAD
         CheckDLOPEN
         CheckClockGettime
         CheckEmscriptenGLES
+        CheckOffscreenVideo
 
         # Set up files for the misc library
         if test x$enable_misc = xyes; then
@@ -4181,7 +4183,6 @@ dnl BeOS support removed after SDL 2.0.1. Haiku still works.  --ryan.
         CheckWerror
         CheckDeclarationAfterStatement
         CheckDummyVideo
-        CheckOffscreenVideo
         CheckDiskAudio
         CheckDummyAudio
         CheckDLOPEN