CMake: Stop using FindOpenGL, which seems to not be required anymore

CMakeLists.txt

@@ -147,9 +147,6 @@ endif()
 # Include bundled CMake modules
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/externals/cmake-modules")
 
-find_package(OpenGL REQUIRED)
-include_directories(${OPENGL_INCLUDE_DIR})
-
 # Prefer the -pthread flag on Linux.
 set (THREADS_PREFER_PTHREAD_FLAG ON)
 find_package(Threads REQUIRED)

externals/glad/CMakeLists.txt

@@ -9,6 +9,7 @@ set(HEADERS
 create_directory_groups(${SRCS} ${HEADERS})
 add_library(glad STATIC ${SRCS} ${HEADERS})
 target_include_directories(glad PUBLIC "include/")
+
 if ("${CMAKE_SYSTEM_NAME}" MATCHES "Linux")
-    target_link_libraries(glad dl)
+    target_link_libraries(glad PRIVATE dl)
 endif()

src/citra/CMakeLists.txt

@@ -19,7 +19,7 @@ include_directories(${SDL2_INCLUDE_DIR})
 
 add_executable(citra ${SRCS} ${HEADERS})
 target_link_libraries(citra PRIVATE common core input_common)
-target_link_libraries(citra PRIVATE ${SDL2_LIBRARY} ${OPENGL_gl_LIBRARY} inih glad)
+target_link_libraries(citra PRIVATE ${SDL2_LIBRARY} inih glad)
 if (MSVC)
     target_link_libraries(citra PRIVATE getopt)
 endif()

src/citra_qt/CMakeLists.txt

@@ -92,7 +92,7 @@ else()
     add_executable(citra-qt ${SRCS} ${HEADERS} ${UI_HDRS})
 endif()
 target_link_libraries(citra-qt PRIVATE audio_core common core input_common video_core)
-target_link_libraries(citra-qt PRIVATE ${OPENGL_gl_LIBRARY} ${CITRA_QT_LIBS} Boost::boost glad)
+target_link_libraries(citra-qt PRIVATE ${CITRA_QT_LIBS} Boost::boost glad)
 target_link_libraries(citra-qt PRIVATE ${PLATFORM_LIBRARIES} Threads::Threads)
 
 if(UNIX AND NOT APPLE)