Fix lack of stack trace on ARM

[relovution]

On ARM, the default installation of this module would produce no stack trace. Example:

root@beaglebone:~/test/node_modules/segfault-handler# node example.js NodeSegfaultHandlerNative: about to dereference NULL (will cause a SIGSEGV) PID 1907 received SIGSEGV for address: 0x2 root@beaglebone:~/test/node_modules/segfault-handler# uname -a Linux beaglebone 4.1.19-bone-rt-r20 #1 Sun Mar 13 04:30:34 UTC 2016 armv7l GNU/Linux

The fix is to build with -funwind-tables as per http://stackoverflow.com/questions/24700150/on-raspberry-pi-backtrace-returns-0-frames:

root@beaglebone:~/test/node_modules/segfault-handler# node example.js NodeSegfaultHandlerNative: about to dereference NULL (will cause a SIGSEGV) PID 2268 received SIGSEGV for address: 0x2 /root/test/node_modules/segfault-handler/build/Release/segfault-handler.node(+0x12a0)[0xb68ba2a0] /lib/arm-linux-gnueabihf/libc.so.6(+0x26b00)[0xb68f1b00] /root/test/node_modules/segfault-handler/build/Release/segfault-handler.node(_Z22segfault_stack_frame_1v+0x1f)[0xb68ba5c4] /root/test/node_modules/segfault-handler/build/Release/segfault-handler.node(+0x1434)[0xb68ba434]

Works on at least ARM and OS X. See also #24.

[cbratschi]

I would also add the -rdynamic compiler flag. Otherwise some details are missing. It is more important to use both flags in your own native modules.