repo syncでfatal: Not a git repository:
$ repo sync -j6 -f
fatal: Not a git repository: '/cygdrive/d/android/master/.repo/projects/abi/cpp.git'
fatal: Not a git repository: '/cygdrive/d/android/master/.repo/projects/bionic.git'
一度フォルダを消す。
$ rm -rf /cygdrive/d/android/master/.repo/projects/abi/cpp.git
$ rm -rf /cygdrive/d/android/master/.repo/projects/bionic.gitもう一度やり直す。
$ repo init -u https://android.googlesource.com/platform/manifest
$ repo sync -j6