[SYCL] Implement thread-local storage restriction (intel#1281)

The SYCL spec was recently clarified to prohibit thread local storage,
so this commit ensures an error is always emitted in these cases.

Additionally, the DeclRefExpr to a VarDecl were switched to delayed
diagnostics.

Signed-off-by: Erich Keane <erich.keane@intel.com>

[SYCL][NFC] Fix static code analysis concerns (intel#1283)

Signed-off-by: Soumi Manna <soumi.manna@intel.com>

2019-12 release

2019-11 release

2019-10 release

2019-09 release

2019-08 release

[SYCL] Enable programs that include system headers on Windows

Add Windows-specific predefined type characteristics for wchar, builtin
VaListKind, and allow the vectorcall attribute on function declarations.
Add Windows support for SPIR target.

Signed-off-by: Melanie Blower <melanie.blower@intel.com>

2019-07 release

[SYCL] Fix handler set_arg(s) method.

Fixed incorrect storing and extractiong of global/constant accessor
in set_arg(s) logic.

Signed-off-by: Alexey Voronov <alexey.voronov@intel.com>