Update glad2 and switch to header-only version

This updates to a newer version of glad2 and switches to the header-only
variant.

This also (finally) switches to the newer glad2 loader signature that
allows us to pass in glfwGetInstanceProcAddress directly.

examples/CMakeLists.txt

@@ -18,8 +18,7 @@ elseif (APPLE)
     set(ICON glfw.icns)
 endif()
 
-set(GLAD_GL "${GLFW_SOURCE_DIR}/deps/glad/gl.h"
-            "${GLFW_SOURCE_DIR}/deps/glad_gl.c")
+set(GLAD_GL "${GLFW_SOURCE_DIR}/deps/glad/gl.h")
 set(GETOPT "${GLFW_SOURCE_DIR}/deps/getopt.h"
            "${GLFW_SOURCE_DIR}/deps/getopt.c")
 set(TINYCTHREAD "${GLFW_SOURCE_DIR}/deps/tinycthread.h"

examples/boing.c

@@ -36,6 +36,7 @@
 #include <stdlib.h>
 #include <math.h>
 
+#define GLAD_GL_IMPLEMENTATION
 #include <glad/gl.h>
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>

examples/gears.c

@@ -31,6 +31,7 @@
 #include <stdio.h>
 #include <string.h>
 
+#define GLAD_GL_IMPLEMENTATION
 #include <glad/gl.h>
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>

examples/heightmap.c

@@ -29,6 +29,7 @@
 #include <assert.h>
 #include <stddef.h>
 
+#define GLAD_GL_IMPLEMENTATION
 #include <glad/gl.h>
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>

examples/offscreen.c

@@ -23,6 +23,7 @@
 //
 //========================================================================
 
+#define GLAD_GL_IMPLEMENTATION
 #include <glad/gl.h>
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>

examples/particles.c

@@ -39,6 +39,7 @@
 #include <getopt.h>
 #include <linmath.h>
 
+#define GLAD_GL_IMPLEMENTATION
 #include <glad/gl.h>
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>

examples/sharing.c

@@ -23,6 +23,7 @@
 //
 //========================================================================
 
+#define GLAD_GL_IMPLEMENTATION
 #include <glad/gl.h>
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>

examples/splitview.c

@@ -10,6 +10,7 @@
 //  because I am not a friend of orthogonal projections)
 //========================================================================
 
+#define GLAD_GL_IMPLEMENTATION
 #include <glad/gl.h>
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>

examples/triangle-opengl.c

@@ -24,6 +24,7 @@
 //========================================================================
 //! [code]
 
+#define GLAD_GL_IMPLEMENTATION
 #include <glad/gl.h>
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>

examples/wave.c

@@ -17,6 +17,7 @@
 #include <stdlib.h>
 #include <math.h>
 
+#define GLAD_GL_IMPLEMENTATION
 #include <glad/gl.h>
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>

examples/windows.c

@@ -23,6 +23,7 @@
 //
 //========================================================================
 
+#define GLAD_GL_IMPLEMENTATION
 #include <glad/gl.h>
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>