Fix for missing exports (fixes #227)

Fix LOG_EVERY_N with clang -Wunused-local-typedef

This compile time assert is no longer used anywhere in glog. Remove
it.

Run src/windows/preprocess.sh to pick up latest logging.h.in changes

Glog uses a pre-C++11 compile time assert to verify the validity of
the severity parameter for LOG_EVERY_N. Unfortunately, some compilers
will complain about the usage of LOG_EVERY_N with
"-Wunused-local-typedef" due to the way the compile time assert is
constructed. This makes it impossible to use LOG_EVERY_N with this
warning treated as an error.

The fix simply removes the assert entirely. This is safe to do since
you can't put anything invalid into the severity parameters without
generating a compile error elsewhere. This has been safe to do ever
since the GLOG_ prefixes were added as part of 6febec36.

Fixes #223

Commit changes to src/windows/glog/logging.h that were missed in
2df0ca34. Because a change to src/glog/logging.h.in was made,
src/windows/preprocess.sh needed to be run.

Update Windows docs

Revert "configure.ac: Allow user to disable gflags"

configure.ac: Allow user to disable gflags

cmake: fixed gflags namespace detection (fixes #193)

This commit fixes gflags namespace detection using Intel compiler and ensures
the generated try_compile command line does not produce malformed paths.

cmake: do not hardcode relative install directories

cmake: changed project name from google-glog to glog

Cygwin support

[RFC] reduce heap memory allocations to zero

rate limit calls to posix_fadvise()

Use gflags ALIAS instead of ${gflags_XXX} vars

Port stack tracing to Windows

This method ensure that all users of glog get automatically linked to
the DbgHelp library without needing to set compiler flags.

Necessary when building with BUILD_SHARED_LIBS=1.

The gflags project updated their CMake config last year with a
`gflags` ALIAS target. This can be used instead of the legacy
`${gflags_LIBRARIES}` and `${gflags_INCLUDE_DIRS}` variables. It also
looks cleaner.

Fixes #198

Remove files generated by autotools

closes #165 

for #165. I think not many projects have them in their repo.

Backport internal changes