It is possible to create a type-safe version of FlagRegisterer
ctor (as well as some internal gflags classes), that will deduce
type of the new flag automatically.

This results in removing quite a few calls to strcmp() when new
flag is created.

No existing behavior change.

From #99, “Given that there is an unsigned flag type for 64-bit
integers, it is probably reasonable to request/expect the same for
32-bit integers.”

find_package COMPONENTS

This reverts commit 02f31897.

Update issue 79
Added a test which uses gflags_declare.h as any other project would use it to avoid such avoidable build configuration mistakes.

Add link dependency on shlwapi.lib during build configuration instead of #pragma comment statement. Use this library also on MinGW.

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.