Initialize with contents in the Flutter buildroot. Imported from https://github.com/flutter/buildroot/tree/430b57c643883e6090b5af09faddd8048efee57c. Only an extra .gitignore has been added. Change-Id: Ibca759b00d2d894e714ef5743b15bbc4c63086e4 Reviewed-on: https://flutter-review.googlesource.com/c/third_party/libxml/+/24223 Reviewed-by: Jason Simmons <jsimmons@google.com> Commit-Queue: Chinmay Garde <chinmaygarde@google.com>