Hush compiler warnings when compiling c code.

ppapi/lib/gl/gles2/gl2ext_ppapi.c

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ppapi/lib/gl/gles2/gl2ext_ppapi.h"
 
 #include <stddef.h>
 
 #ifndef GL_FALSE
 #define GL_FALSE 0
@@ skipping 58 matching lines @@
     g_gles2_chromium_map_sub_interface =
         get_browser_interface(PPB_OPENGLES2_CHROMIUMMAPSUB_INTERFACE);
   }
   if (!g_gles2_query_interface) {
     g_gles2_query_interface =
         get_browser_interface(PPB_OPENGLES2_QUERY_INTERFACE);
   }
   return g_gles2_interface ? GL_TRUE : GL_FALSE;
 }
 
-GLboolean GL_APIENTRY glTerminatePPAPI() {
+GLboolean GL_APIENTRY glTerminatePPAPI(void) {
   g_gles2_interface = NULL;
   return GL_TRUE;
 }
 
 void GL_APIENTRY glSetCurrentContextPPAPI(PP_Resource context) {
   g_current_context = context;
 }
 
-PP_Resource GL_APIENTRY glGetCurrentContextPPAPI() {
+PP_Resource GL_APIENTRY glGetCurrentContextPPAPI(void) {
   return g_current_context;
 }
 
-const struct PPB_OpenGLES2* GL_APIENTRY glGetInterfacePPAPI() {
+const struct PPB_OpenGLES2* GL_APIENTRY glGetInterfacePPAPI(void) {
   return g_gles2_interface;
 }
 
 const struct PPB_OpenGLES2InstancedArrays* GL_APIENTRY
-    glGetInstancedArraysInterfacePPAPI() {
+    glGetInstancedArraysInterfacePPAPI(void) {
   return g_gles2_instanced_arrays_interface;
 }
 
 const struct PPB_OpenGLES2FramebufferBlit* GL_APIENTRY
-    glGetFramebufferBlitInterfacePPAPI() {
+    glGetFramebufferBlitInterfacePPAPI(void) {
   return g_gles2_framebuffer_blit_interface;
 }
 
 const struct PPB_OpenGLES2FramebufferMultisample* GL_APIENTRY
-    glGetFramebufferMultisampleInterfacePPAPI() {
+    glGetFramebufferMultisampleInterfacePPAPI(void) {
   return g_gles2_framebuffer_multisample_interface;
 }
 
 const struct PPB_OpenGLES2ChromiumEnableFeature* GL_APIENTRY
-    glGetChromiumEnableFeatureInterfacePPAPI() {
+    glGetChromiumEnableFeatureInterfacePPAPI(void) {
   return g_gles2_chromium_enable_feature_interface;
 }
 
 const struct PPB_OpenGLES2ChromiumMapSub* GL_APIENTRY
-    glGetChromiumMapSubInterfacePPAPI() {
+    glGetChromiumMapSubInterfacePPAPI(void) {
   return g_gles2_chromium_map_sub_interface;
 }
 
 const struct PPB_OpenGLES2Query* GL_APIENTRY
-    glGetQueryInterfacePPAPI() {
+    glGetQueryInterfacePPAPI(void) {
   return g_gles2_query_interface;
 }