[build] CMake: support OpenGL ES3 in `LibraryConfigurations.cmake` (#4079)

* Allow ES3 in LibraryConfigurations.cmake

* Put FULL_ES3 as linker option

cmake/LibraryConfigurations.cmake

@@ -58,7 +58,9 @@ if (${PLATFORM} MATCHES "Desktop")
 
 elseif (${PLATFORM} MATCHES "Web")
     set(PLATFORM_CPP "PLATFORM_WEB")
-    set(GRAPHICS "GRAPHICS_API_OPENGL_ES2")
+    if(NOT GRAPHICS)
+        set(GRAPHICS "GRAPHICS_API_OPENGL_ES2")
+    endif()
     set(CMAKE_STATIC_LIBRARY_SUFFIX ".a")
 
 elseif (${PLATFORM} MATCHES "Android")

src/CMakeLists.txt

@@ -70,6 +70,9 @@ endif()
 
 if (${PLATFORM} MATCHES "Web")
     target_link_options(raylib PUBLIC "-sUSE_GLFW=3")
+    if(${GRAPHICS} MATCHES "GRAPHICS_API_OPENGL_ES3")
+        target_link_options(raylib PUBLIC "-sFULL_ES3=1")
+    endif()
 endif()
 
 set_target_properties(raylib PROPERTIES