ANGLE should build with -Wshorten-64-to-32

ANGLE should build with -Wshorten-64-to-32
<http://webkit.org/b/106798>
<http://code.google.com/p/angleproject/issues/detail?id=396>

Reviewed by Kenneth Russell.

Most changes below are simply to document issues with #pragma
statements per request by upstream.  The change to osinclude.h
is the only bug fix, which defines OS_TLSIndex in terms of
pthread_key_t instead of unsigned int since pthread_key_t is a
64-bit value on 64-bit Mac OS X.

* Configurations/Base.xcconfig: Enable -Wshorten-64-to-32 by
setting GCC_WARN_64_TO_32_BIT_CONVERSION to YES.
* src/compiler/Intermediate.cpp:
(TIntermTraverser::hash): Add #pragmas for clang to ignore
-Wshorten-64-to-32 warning.
* src/compiler/MapLongVariableNames.cpp:
(LongNameMap::Size): Ditto.
* src/compiler/ShaderLang.cpp:
(getVariableInfo): Ditto.
(ShGetInfo): Ditto.
* src/compiler/ValidateLimitations.cpp:
(ValidateLimitations::validateFunctionCall): Ditto.
* src/compiler/glslang.l: Ditto.
* src/compiler/glslang_lex.cpp: Ditto.
* src/compiler/osinclude.h: Change type of OS_TLSIndex to
pthread_key_t.  Define OS_INVALID_TLS_INDEX by using
static_cast<OS_TLSIndex>(-1).
* src/compiler/preprocessor/Input.cpp:
(pp::Input::Input): Add #pragmas for clang to ignore
-Wshorten-64-to-32 warning.
* src/compiler/preprocessor/Tokenizer.cpp: Ditto.
* src/compiler/preprocessor/Tokenizer.l: Ditto.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@139758 268f45cc-cd09-0410-ab3c-d52691b4dbfc