Merge remote-tracking branch 'aosp/upstream-master' into update-shaderc

Includes:
c607253 Avoid -fPIC for MinGW builds
1927f30 Allow override of SPVTOOLS_LOCAL_PATH
bcadbc1 Move spirv-tools build from third_party/Android.mk
3fde660 Update CHANGES
c815335 Adapt to Glslang generator version number change
259ca18 Travis CI: use make to build
16f8253 Add HLSL legalization passes to compiler.cc
e089609 Add SPIRV-Tools optimizer files for linker
84c9dd9 Added more opt passes to PassId enum
b58a21a Fix typos in README.md
5c4fd69 Allow SPIRV-Headers to be checked out at third_party/
c677f26 Include SPIRV-Tools before glslang
8aa64c6 Appveyor: stop downloading pip
c8ba3e4 Check _WIN32 instead of WIN32 for building shared library
00c9fe4 Appveyor: Stop deploying to BinTray
97e0e13 Appveyor: deploy to BinTray instead of GitHub Release page
0b99bfa Serialize inclusions by the CountingIncluder
4cdf49e Fix the build by changing deploy repo
6db3870 Deploy Appveyor build artifacts to GitHub Releases
7ad5b69 SPIRV-Tools added source/validate_bitwise.cpp
4138101 SPIRV-Tools added source/opt/eliminate_dead_functions_pass.cpp
61eb9ff Android: Fix generation of 1.2 grammar tables
c77e1e9 SPIRV-Tools added source/validate_logicals.cpp
eadd549 SPIRV-Tools added source/opt/strength_reduction_pass.cpp
c56b7dc Add shared library variant for libshaderc
777c9ff SPIRV-Tools added validate_arithmetics.cpp

Test: checkbuild.py on Linux; unit tests on Windows
Change-Id: Iea56c8d560ce09a38f03a89067629e47b40e1def