Remove OSMesa specific code from offscreen example

The OSMesa specific path is more appropriate for a test than an example.

examples/CMakeLists.txt

@@ -50,11 +50,6 @@ set_target_properties(${GUI_ONLY_BINARIES} ${CONSOLE_BINARIES} PROPERTIES
                       C_STANDARD 99
                       FOLDER "GLFW3/Examples")
 
-if (GLFW_USE_OSMESA)
-    find_package(OSMesa REQUIRED)
-    target_compile_definitions(offscreen PRIVATE USE_NATIVE_OSMESA)
-endif()
-
 if (MSVC)
     # Tell MSVC to use main instead of WinMain
     set_target_properties(${GUI_ONLY_BINARIES} PROPERTIES

examples/offscreen.c

@@ -28,11 +28,6 @@
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>
 
-#if USE_NATIVE_OSMESA
- #define GLFW_EXPOSE_NATIVE_OSMESA
- #include <GLFW/glfw3native.h>
-#endif
-
 #include "linmath.h"
 
 #include <stdlib.h>
@@ -151,24 +146,16 @@ int main(void)
     glDrawArrays(GL_TRIANGLES, 0, 3);
     glFinish();
 
-#if USE_NATIVE_OSMESA
-    glfwGetOSMesaColorBuffer(window, &width, &height, NULL, (void**) &buffer);
-#else
     buffer = calloc(4, width * height);
     glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
-#endif
 
     // Write image Y-flipped because OpenGL
     stbi_write_png("offscreen.png",
                    width, height, 4,
                    buffer + (width * 4 * (height - 1)),
                    -width * 4);
 
-#if USE_NATIVE_OSMESA
-    // Here is where there's nothing
-#else
     free(buffer);
-#endif
 
     glfwDestroyWindow(window);