misc: replace NULL with nullptr.

src/gpu/vertexbuffer.cpp

@@ -310,7 +310,7 @@ void VertexDeclaration::SetStream(VertexBuffer *vb, ShaderAttrib attr1,
 {
 #if defined _XBOX || defined USE_D3D9
     // Don't bother in DirectX world, shader attributes are not used
-    SetStream(vb, NULL);
+    SetStream(vb, nullptr);
 #else
     ShaderAttrib attribs[12] = { attr1, attr2, attr3, attr4, attr5, attr6,
                            attr7, attr8, attr9, attr10, attr11, attr12 };

src/image/codec/gdiplus-image.cpp

@@ -138,7 +138,7 @@ bool GdiPlusImageCodec::Save(Image *image, char const *path)
 {
     ULONG_PTR token;
     Gdiplus::GdiplusStartupInput input;
-    Gdiplus::GdiplusStartup(&token, &input, NULL);
+    Gdiplus::GdiplusStartup(&token, &input, nullptr);
 
     wchar_t const *fmt;
     if (strstr(path, ".gif"))
@@ -173,7 +173,7 @@ bool GdiPlusImageCodec::Save(Image *image, char const *path)
     }
 
     size_t len;
-    len = mbstowcs(NULL, path, 0);
+    len = mbstowcs(nullptr, path, 0);
     wchar_t *wpath = new wchar_t[len + 1];
     if (mbstowcs(wpath, path, len + 1) == (size_t)-1)
     {
@@ -212,7 +212,7 @@ bool GdiPlusImageCodec::Save(Image *image, char const *path)
     image->Unlock(pdst);
     b->UnlockBits(&bdata);
 
-    if (b->Save(wpath, &clsid, NULL) != Gdiplus::Ok)
+    if (b->Save(wpath, &clsid, nullptr) != Gdiplus::Ok)
     {
         Log::Error("could not save GDI+ image '%s'\n", path);
         delete[] wpath;

src/platform/ps3/ps3app.cpp

@@ -224,7 +224,7 @@ Ps3App::Ps3App(char const *title, ivec2 res, float fps) :
 
     sys_ppu_thread_t thread;
     ret = sys_ppu_thread_create(&thread, Ps3AppData::MultiStreamThread,
-                                NULL, 0 /* Server prio */,
+                                nullptr, 0 /* Server prio */,
                                 0x4000 /* 16 KiB stack */,
                                 SYS_PPU_THREAD_CREATE_JOINABLE,
                                 "Audio Thread");

src/sys/file.cpp

@@ -75,7 +75,7 @@ class FileData
 #if __CELLOS_LV2__
         String realfile = String(SYS_APP_HOME) + '/' + file;
         CellFsErrno err = cellFsOpen(realfile.C(), CELL_FS_O_RDONLY,
-                                     &m_fd, NULL, 0);
+                                     &m_fd, nullptr, 0);
         if (err != CELL_FS_SUCCEEDED)
             m_fd = -1;
 #elif __ANDROID__

src/sys/thread.cpp

@@ -98,7 +98,7 @@ void *BaseThreadManager::BaseThreadWork(void* data)
         }
     }
     that->m_donequeue.Push(ThreadStatus::THREAD_STOPPED);
-    return NULL;
+    return nullptr;
 }
 
 void BaseThreadManager::TickGame(float seconds)