This commit addresses a few issues:

    1.  No longer leak config.h in a way similar to
            https://github.com/gflags/gflags/issues/233
        The solution of prefixing the path by 'glog_internal' is modified from
            https://github.com/gflags/gflags/issues/234

    2.  No longer expose internal headers.

    3.  Replace PACKAGE_NAME with native.package_name()

    4.  Uers can choose namespaces via the newly added 'namespace' keyword.

    5.  Replace glob with explicitly listing of files.

    6.  Make the genrules more compact using pythonic list construction.

Compute base addresses from program headers while reading /proc/self/maps.

We previously had logic to compute the base address from program
headers as part of symbolization. The problem is that we need a correct
base address earlier in order to adjust a PC into the image's address
space, as these addresses can appear in unsymbolized output.

There was previously an assumption that only the mapping that
was lowest in the address space did not need to be adjusted. This
assumption is not guaranteed (for example, the kernel may choose to
map an ET_DYN lowest) and in fact turned out to be wrong in binaries
linked with lld because the first mapping is read-only.

The solution is to move the program header reading logic into the
code that reads /proc/self/maps.

There is a change in semantics for clients that install a callback
using the InstallSymbolizeOpenObjectFileCallback function. Any such
clients will need to return a correct base address from the callback
by reading program headers using code similar to that in the function
OpenObjectFileContainingPcAndGetStartAddress.

Cache strlen outside of cycles (PVS-Studio)

Shell escape arguments to /bin/mail.

Fix username lookup in case of missing USER environment variable

#253: Use MS preprocessor idiom to disable warning

Zero allocation fix

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