bug: cygwin support breaks cross compiles on cygwin

[Patrick Georgi]

Hi,

I used cygwin to build grub2/i386-coreboot using an i386-elf cross 
compiler. unfortunately the test in configure only looks for the host 
platform and enables pe2elf in that case, even though my compiler emits 
ELF already.

my workaround is to just change that test (there's no OS cyg_win), but 
of course that's no permanent solution.
Bean proposed on IRC to look if the target compiler emits PE, and enable 
pe2elf based on that.


Regards,
Patrick Georgi