Remove old clang-cl workaround

According to the upstream bug report [1], this bug has been fixed
already. So remove the now useless workaround.

[1] https://bugs.llvm.org/show_bug.cgi?id=41226

Change-Id: I7e17750f9e47fb9a0f8315ca15f89b741b107a35
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/global/qt_pch.h

@@ -26,11 +26,6 @@
 # define _POSIX_
 # include <limits.h>
 # undef _POSIX_
-#        if defined(Q_CC_CLANG) && defined(Q_CC_MSVC)
-// See https://bugs.llvm.org/show_bug.cgi?id=41226
-#            include <wchar.h>
-__declspec(selectany) auto *__wmemchr_symbol_loader_value = wmemchr(L"", L'0', 0);
-#        endif
 #    endif
 #    include <qcoreapplication.h>
 #    include <qcoreevent.h>