configure: remove obsolete OpenGL option

The OpenGL output device was removed, but configure still exposed --enable-opengl and probed OpenGL headers and functions.

Remove the stale option, dependency checks, configure probes, and related device metadata.

Signed-off-by: Ruonan <yu_ruonan@outlook.com>

MAINTAINERS

@@ -323,7 +323,6 @@ libavdevice
   iec61883.c                            Georg Lippitsch
   lavfi                                 Stefano Sabatini
   libdc1394.c                           Roman Shaposhnik
-  opengl_enc.c                          Lukasz Marek
   pulse_audio_enc.c                     Lukasz Marek
   sdl                                   Stefano Sabatini
   sdl2.c                                Josh de Kock

configure

@@ -334,7 +334,6 @@ External library support:
   --enable-ohcodec         enable OpenHarmony Codec support [no]
   --enable-openal          enable OpenAL 1.1 capture support [no]
   --enable-opencl          enable OpenCL processing [no]
-  --enable-opengl          enable OpenGL rendering [no]
   --enable-openssl         enable openssl, needed for https support
                            if gnutls, libtls or mbedtls is not used [no]
   --enable-pocketsphinx    enable PocketSphinx, needed for asr filter [no]
@@ -2143,7 +2142,6 @@ EXTERNAL_LIBRARY_LIST="
     mediacodec
     ohcodec
     openal
-    opengl
     openssl
     pocketsphinx
     vapoursynth
@@ -2455,7 +2453,6 @@ HEADERS_LIST="
     dirent_h
     dxgidebug_h
     dxva_h
-    ES2_gl_h
     gsm_h
     io_h
     linux_dma_buf_h
@@ -2520,7 +2517,6 @@ SYSTEM_FUNCS="
     GetSystemTimeAsFileTime
     gettimeofday
     glob
-    glXGetProcAddress
     gmtime_r
     inet_aton
     ioctl
@@ -2563,7 +2559,6 @@ SYSTEM_FUNCS="
     usleep
     UTGetOSTypeFromString
     VirtualAlloc
-    wglGetProcAddress
 "
 
 SYSTEM_LIBRARIES="
@@ -7467,13 +7462,6 @@ enabled opencl            && { check_pkg_config opencl OpenCL CL/cl.h clEnqueueN
                              { test_cpp_condition "OpenCL/cl.h" "defined(CL_VERSION_1_2)" ||
                                test_cpp_condition "CL/cl.h" "defined(CL_VERSION_1_2)" ||
                                die "ERROR: opencl must be installed and version must be 1.2 or compatible"; }
-enabled opengl            && { check_lib opengl GL/glx.h glXGetProcAddress "-lGL" ||
-                               check_lib opengl windows.h wglGetProcAddress "-lopengl32 -lgdi32" ||
-                               check_lib opengl OpenGL/gl3.h glGetError "-framework OpenGL" ||
-                               check_lib opengl ES2/gl.h glGetError "-isysroot=${sysroot} -framework OpenGLES" ||
-                               die "ERROR: opengl not found."
-                             }
-
 enabled openssl           && { { check_pkg_config openssl "openssl >= 3.0.0" openssl/ssl.h DTLS_get_data_mtu &&
                                  { enabled gplv3 || ! enabled gpl || enabled nonfree || die "ERROR: OpenSSL >=3.0.0 requires --enable-version3"; }; } ||
                                { enabled gpl && ! enabled nonfree && die "ERROR: OpenSSL <3.0.0 is incompatible with the gpl"; } ||

doc/general_contents.texi

@@ -1640,7 +1640,6 @@ performance on systems without hardware floating point support).
 @item LIBCDIO           @tab X
 @item LIBDC1394         @tab X      @tab
 @item OpenAL            @tab X
-@item OpenGL            @tab        @tab X
 @item OSS               @tab X      @tab X
 @item PulseAudio        @tab X      @tab X
 @item SDL               @tab        @tab X