Cygwin doesn't work well if we try to capture stderr and stdout at the same time. Comment one test tempraly for Cygwin. Need to figure out why and add the test back for Cygwin.

With AM_PROG_AR may report "error: possibly underfined macro: AM_PROG_AR" (mingw, autoreconf-2.68).
Without AM_PROG_AR may report warning "archiver requires 'AM_PROG_AR' in 'configure.ac'" (cygwin, automake-1.12).
They do not affect the tests and install

2, Verifies the EnumValueDscriptor for DynamicMessage.Builder#setField

Increase the allocated_size_ should be after allocation. Otherwise there might have segmentation fault if allocation throws an exception.

"unary minus operator applied to unsigned type, result still unsigned"

https://codereview.appspot.com/86030044/

Replace TSan API declarations in atomicops_internals_tsan.h with a header inclusion (patch from glider@)

Both gcc and clang defines the __aarch64__ macro when building
for the 64-bit AArch64 execution state of ARMv8 processors, so
use this to detect the architecture.