bug fix: the argument of '--sysroot' option should be followed '=' character.
bug fix: add new option '-mandroid' into CFLAGS and same options are applied into LDFLAGS.
refactoring
add a new feature to select the target architecture.
add a new feature to select the target Android platform.
more CFLAGS and LDFLAGS are specified automatically.
bug fix: fix "--sysroot" option and host platform detection.
support 'Cygwin' as build platform.
bug fix: fix wrong method name.
Merge pull request #975 from crimsonwoods/modify_build_script

Improve Android platform support.