mysql.h location can be both <mysql/mysql.h> and <mysql.h>
errno shouldn't be declared by programmers, errno should be declared
in <errno.h>, furthermore the bionic libc define it as __errno, which is
not an integer as declared in hydra.c, so type mismatch error is fired.
added Android.mk makefile
Merge pull request #4 from tux-mind/master

make hydra compile under the android ndk