Add Nintendo Switch support through CMake

.github/workflows/build-switch.yml

@@ -0,0 +1,26 @@
+name: Build for Nintendo Switch using CMake provided by devkitPro
+on:
+  pull_request:
+  push:
+  release:
+    types: published
+jobs:
+  build-nintendo-switch:
+    runs-on: ubuntu-latest
+    container: devkitpro/devkita64:latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: "Build files"
+        run: |
+          /opt/devkitpro/portlibs/switch/bin/aarch64-none-elf-cmake -S. -Bbuild .. -DLIBRW_PLATFORM=GL3 -DLIBRW_GL3_GFXLIB=GLFW -DLIBRW_INSTALL=True
+          cmake --build build -j
+      - name: "Create binary package (cpack)"
+        working-directory: ./build
+        run: |
+          cpack
+      - name: "Archive binary package (github artifacts)"
+        uses: actions/upload-artifact@v2
+        with:
+          name: "switch-gl3"
+          path: build/*.tar.xz
+          if-no-files-found: error

CMakeLists.txt

@@ -100,6 +100,8 @@ if(LIBRW_INSTALL)
             set(os "-apple")
         elseif(UNIX)
             set(os "-linux")
+        elseif(NINTENDO_SWITCH)
+            set(os "-switch")
         else()
             set(compiler "-UNK")
             message(WARNING "Unknown os. Created cpack package will be wrong. (override using cpack -P)")

src/CMakeLists.txt

@@ -148,13 +148,16 @@ set_target_properties(librw
 )
 
 if(LIBRW_PLATFORM_GL3)
-    set(OpenGL_GL_PREFERENCE GLVND)
-    find_package(OpenGL REQUIRED)
+    if(NOT NINTENDO_SWITCH)
+        set(OpenGL_GL_PREFERENCE GLVND)
+        find_package(OpenGL REQUIRED)
+
+        target_link_libraries(librw
+            PUBLIC
+                OpenGL::GL
+        )
+    endif()
 
-    target_link_libraries(librw
-        PUBLIC
-            OpenGL::GL
-    )
     if (LIBRW_GL3_GFXLIB STREQUAL "GLFW")
         find_package(glfw3 REQUIRED)
         target_link_libraries(librw
@@ -175,6 +178,15 @@ if(LIBRW_PLATFORM_GL3)
             )
         endif()
     endif()
+
+    if(NINTENDO_SWITCH)
+        target_link_libraries(librw
+            PUBLIC
+                EGL
+                glapi
+                drm_nouveau
+        )
+    endif()
 elseif(LIBRW_PLATFORM_D3D9)
     target_link_libraries(librw
         PUBLIC