tdf#161048 Revert "move opencl check at startup inside its own thread"

This reverts commit 7d1242b01d.

Intel's OpenCL driver gets stuck during shutdown and blocks the process from exiting

Change-Id: I0e1360fd183dacd7331e1dd4122154d705f567fa
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/168067
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Jenkins

desktop/inc/app.hxx

@@ -169,7 +169,6 @@ class Desktop final : public Application
         std::unique_ptr<Lockfile> m_xLockfile;
         Timer                   m_firstRunTimer;
         std::thread             m_aUpdateThread;
-        std::thread             m_aOpenCLCheckThread;
 };
 
 OUString GetURL_Impl(

desktop/source/app/app.cxx

@@ -1613,7 +1613,7 @@ int Desktop::Main()
 
         // FIXME: move this somewhere sensible.
 #if HAVE_FEATURE_OPENCL
-        m_aOpenCLCheckThread = std::thread(CheckOpenCLCompute, xDesktop);
+        CheckOpenCLCompute(xDesktop);
 #endif
 
 #if !defined(EMSCRIPTEN)
@@ -1670,9 +1670,6 @@ int Desktop::doShutdown()
     if (m_aUpdateThread.joinable())
         m_aUpdateThread.join();
 
-    if (m_aOpenCLCheckThread.joinable())
-        m_aOpenCLCheckThread.join();
-
     if (pExecGlobals->xJVMloadThread.is())
     {
         pExecGlobals->xJVMloadThread->join();