Build is broken on Mac

[franciozzy]

I just realised that commit 1570efc02cb2bd3aa2564e3a2ebe77249279af4b is incompatible with building on Yosemite and El Capitan.

When trying to build, I get -static instead of -D__APPLE__ which causes the following:

gcc  -Wall -static -o lpc21isp lpc21isp.c adprog.o lpcprog.o lpcterm.o
ld: library not found for -lcrt0.o
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [lpc21isp] Error 1

To fix it, I have reverted that commit. Could you please fix that on your branch? Or maybe change that test to support both "darwin" and "Darwin" ?

[leandron]

Still broken for macOS Sierra. Changing darwin to Darwin fix the problem as reported by @franciozzy.