Use of isalpha(), islower(), isspace() macros throw a warning, and due use of -Werror, an error.
Files effected: cpu/or32/or32.c, cpu/or32/generate.c, sim-cmd.c
Can be fixed by casting all chars as int.
Error in peripheral/eth.h: "MSG_DONTWAIT" redefined from /usr/include/netinet/in.h
Fixed by removing MSG_DONTWAIT
I recall adding this, but I guess it can be removed again.
That was to be all the issues I encountered while building under Cygwin 7.
Note that it was gcc-3.4.4 under Cygwin 1.7.7.
... and that there's no such thing as Cygwin 7! (Windows machine is running XP 32-bit, not that it matters, I believe.)