Tweak CMake build on Cygwin.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146725 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/cmake/modules/HandleLLVMOptions.cmake b/cmake/modules/HandleLLVMOptions.cmake
index 6788f8e..c316ab6 100644
--- a/cmake/modules/HandleLLVMOptions.cmake
+++ b/cmake/modules/HandleLLVMOptions.cmake
@@ -76,7 +76,7 @@
     # Xcode has -mdynamic-no-pic on by default, which overrides -fPIC. I don't
     # know how to disable this, so just force ENABLE_PIC off for now.
     message(WARNING "-fPIC not supported with Xcode.")
-  elseif( WIN32 )
+  elseif( WIN32 OR CYGWIN)
     # On Windows all code is PIC. MinGW warns if -fPIC is used.
   else()
     include(CheckCXXCompilerFlag)