Merge branch 'jn/thinner-wrapper'

* jn/thinner-wrapper: Remove pack file handling dependency from wrapper.o pack-objects: mark file-local variable static wrapper: give zlib wrappers their own translation unit strbuf: move strbuf_branchname to sha1_name.c path helpers: move git_mkstemp* to wrapper.c wrapper: move odb_* to environment.c wrapper: move xmmap() to sha1_file.c