Both GFLAGS_NAMESPACE and GFLAGS_INCLUDE_DIR can be used to customize the installation of the gflags library. One specifies the C++ namespace name of the gflags symbols, the other the include subdirectory path of the public header files. By default, both are set to "gflags", but other Google libraries still expect "google" as C++ namespace name, but not necessarily also include path.

Both GFLAGS_NAMESPACE and GFLAGS_INCLUDE_DIR can be used to customize the installation of the gflags library. One specifies the C++ namespace name of the gflags symbols, the other the include subdirectory path of the public header files. By default, both are set to "gflags", but other Google libraries still expect "google" as C++ namespace name, but not necessarily also include path.

Expose as few system variables as possible through public interface.
Perform STRIP_FLAGS_HELP test using CMake instead of Bash.
Change file path separator used by gflags_reporting.cc to backslash on Windwos.

Configure and install CMake package configuration file to help find_package locate the gflags package.