autoconf: Add --disable-embed-stdcxx to suppress linking libstdc++.a into llvm.dll with --enable-shared on Cygming.

Cygwin has stdc++.dll in it's distribution, and we can assume distro's stdc++.dll might be available.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122622 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed