[Vm-dev] [OpenSmalltalk/opensmalltalk-vm] 2bae43: libgit2: don't put /usr in the FIND_ROOT_PATH

[GitHub]

  Branch: refs/heads/build_pharo_win32_with_cygwin
  Home:   https://github.com/OpenSmalltalk/opensmalltalk-vm
  Commit: 2bae43f13c1e3e1a0d80488e634db8d38448b03a
      https://github.com/OpenSmalltalk/opensmalltalk-vm/commit/2bae43f13c1e3e1a0d80488e634db8d38448b03a
  Author: nicolas-cellier-aka-nice <nicolas.cellier.aka.nice at gmail.com>
  Date:   2017-03-18 (Sat, 18 Mar 2017)

  Changed paths:
    M build.win32x86/third-party/Toolchain-cross-mingw32-cygwin.cmake

  Log Message:
  -----------
  libgit2: don't put /usr in the FIND_ROOT_PATH

Otherwise, cmake will find some cygwin files incompatible for cross compilation to mingw32
I don't know why the build did succeed once in cygwin64, it does not in cygwin32 without this fix.