Cygwin, configure and mmap

Hello list.

I am attempting to build llvm, clang, compile-rt, and lldb using
Cygwin. (don't ask)

I am using the 3.3 tag.

I have the following problems.

1 - Running configure,
CC=/bin/gcc CXX=/bin/g++ ../llvm-3-3/configure --enable-optimized

I see the following message:

configure: WARNING: mmap() of a fixed address required but not supported

I have seen various postings on the Web that there is an issue with
configure, Cygwin and mmap().

I didn't see this issue in the FAQs.

Is this warning a concern?