[client] opengl: add gl_dynprocs module

This is similar to egl_dynprocs, except for OpenGL functions.

client/include/gl_dynprocs.h

@@ -0,0 +1,50 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2021 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _H_LG_GL_DYNPROCS_
+#define _H_LG_GL_DYNPROCS_
+#ifdef ENABLE_OPENGL
+
+#include <GL/gl.h>
+#include <GL/glext.h>
+
+struct GLDynProcs
+{
+  PFNGLGENBUFFERSPROC     glGenBuffers;
+  PFNGLBINDBUFFERPROC     glBindBuffer;
+  PFNGLBUFFERDATAPROC     glBufferData;
+  PFNGLBUFFERSUBDATAPROC  glBufferSubData;
+  PFNGLDELETEBUFFERSPROC  glDeleteBuffers;
+  PFNGLISSYNCPROC         glIsSync;
+  PFNGLFENCESYNCPROC      glFenceSync;
+  PFNGLCLIENTWAITSYNCPROC glClientWaitSync;
+  PFNGLDELETESYNCPROC     glDeleteSync;
+  PFNGLGENERATEMIPMAPPROC glGenerateMipmap;
+};
+
+extern struct GLDynProcs g_gl_dynProcs;
+
+void gl_dynProcsInit(void);
+
+#else
+  #define gl_dynProcsInit(...)
+#endif
+
+#endif // _H_LG_GL_DYNPROCS_