WGL: Add extension function macro aliases

This should have been done when the WGL extension members were moved
from the context struct to the library struct.

(cherry picked from commit 22a6c02a4c)

src/wgl_context.c

@@ -77,7 +77,7 @@ static int choosePixelFormat(_GLFWwindow* window,
     {
         const int attrib = WGL_NUMBER_PIXEL_FORMATS_ARB;
 
-        if (!_glfw.wgl.GetPixelFormatAttribivARB(window->context.wgl.dc,
+        if (!wglGetPixelFormatAttribivARB(window->context.wgl.dc,
                                           1, 0, 1, &attrib, &nativeCount))
         {
             _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
@@ -141,7 +141,7 @@ static int choosePixelFormat(_GLFWwindow* window,
         {
             // Get pixel format attributes through "modern" extension
 
-            if (!_glfw.wgl.GetPixelFormatAttribivARB(window->context.wgl.dc,
+            if (!wglGetPixelFormatAttribivARB(window->context.wgl.dc,
                                               pixelFormat, 0,
                                               attribCount,
                                               attribs, values))
@@ -362,7 +362,7 @@ static void swapIntervalWGL(int interval)
     }
 
     if (_glfw.wgl.EXT_swap_control)
-        _glfw.wgl.SwapIntervalEXT(interval);
+        wglSwapIntervalEXT(interval);
 }
 
 static int extensionSupportedWGL(const char* extension)
@@ -370,9 +370,9 @@ static int extensionSupportedWGL(const char* extension)
     const char* extensions = NULL;
 
     if (_glfw.wgl.GetExtensionsStringARB)
-        extensions = _glfw.wgl.GetExtensionsStringARB(wglGetCurrentDC());
+        extensions = wglGetExtensionsStringARB(wglGetCurrentDC());
     else if (_glfw.wgl.GetExtensionsStringEXT)
-        extensions = _glfw.wgl.GetExtensionsStringEXT();
+        extensions = wglGetExtensionsStringEXT();
 
     if (!extensions)
         return GLFW_FALSE;
@@ -695,8 +695,7 @@ GLFWbool _glfwCreateContextWGL(_GLFWwindow* window,
         setAttrib(0, 0);
 
         window->context.wgl.handle =
-            _glfw.wgl.CreateContextAttribsARB(window->context.wgl.dc,
-                                              share, attribs);
+            wglCreateContextAttribsARB(window->context.wgl.dc, share, attribs);
         if (!window->context.wgl.handle)
         {
             const DWORD error = GetLastError();

src/wgl_context.h

@@ -76,11 +76,17 @@
 #define ERROR_INVALID_PROFILE_ARB 0x2096
 #define ERROR_INCOMPATIBLE_DEVICE_CONTEXTS_ARB 0x2054
 
+// WGL extension pointer typedefs
 typedef BOOL (WINAPI * PFNWGLSWAPINTERVALEXTPROC)(int);
 typedef BOOL (WINAPI * PFNWGLGETPIXELFORMATATTRIBIVARBPROC)(HDC,int,int,UINT,const int*,int*);
 typedef const char* (WINAPI * PFNWGLGETEXTENSIONSSTRINGEXTPROC)(void);
 typedef const char* (WINAPI * PFNWGLGETEXTENSIONSSTRINGARBPROC)(HDC);
 typedef HGLRC (WINAPI * PFNWGLCREATECONTEXTATTRIBSARBPROC)(HDC,HGLRC,const int*);
+#define wglSwapIntervalEXT _glfw.wgl.SwapIntervalEXT
+#define wglGetPixelFormatAttribivARB _glfw.wgl.GetPixelFormatAttribivARB
+#define wglGetExtensionsStringEXT _glfw.wgl.GetExtensionsStringEXT
+#define wglGetExtensionsStringARB _glfw.wgl.GetExtensionsStringARB
+#define wglCreateContextAttribsARB _glfw.wgl.CreateContextAttribsARB
 
 // opengl32.dll function pointer typedefs
 typedef HGLRC (WINAPI * PFN_wglCreateContext)(HDC);