[Cygwin] Don't use version script for Cygwin target (#143133)

Cygwin is a COFF platform and does not support version-script.
I guess I should use LLVM_HAVE_LINK_VERSION_SCRIPT here, but I don't
know why this is not currently the case.

Author: kikairoya

llvm/tools/llvm-shlib/CMakeLists.txt

@@ -66,7 +66,7 @@ if(LLVM_BUILD_LLVM_DYLIB)
     else()
       # GNU ld doesn't resolve symbols in the version script.
       set(LIB_NAMES -Wl,--whole-archive ${LIB_NAMES} -Wl,--no-whole-archive)
-      if (NOT LLVM_LINKER_IS_SOLARISLD AND NOT MINGW)
+      if (NOT LLVM_LINKER_IS_SOLARISLD AND NOT MINGW AND NOT CYGWIN)
         # Solaris ld does not accept global: *; so there is no way to version *all* global symbols
         set(LIB_NAMES -Wl,--version-script,${LLVM_LIBRARY_DIR}/tools/llvm-shlib/simple_version_script.map ${LIB_NAMES})
       endif()