Rationale: on Android one must use UsbManager, to access any
USB device. As a result, libraries like libusb can only use file descriptors
that are provided by UsbManager.
libusb has an API to use such file descriptors: hid_libusb_wrap_sys_device.
Having hid_libusb_wrap_sys_device currently is the only way to make hidapi
work on Android without root access and without custom Android builds.
Relevant info: https://github.com/libusb/libusb/pull/830/files
m4/ax_pthread.m4 says that PTHREAD_CFLAGS needs to be provided to the
linker line as well as the compile line. This enables static library
builds of hidapi.
This adds the familiar autotools build system and associated documentation
for Linux, FreeBSD, Mac, MinGW, and Cygwin. The old Makefiles have been
kept, and where appropriate have been renamed Makefile-manual.
Thanks to Peter Stuge, Ludovic Rousseau, Xiaofan Chen, Alex Dupre, and
Segher Boessenkool for providing testing, review, and suggestions, and to
Ludovic Rousseau for providing patches which contributed to this commit.
Ihor Dutchak