Merge branch 'sp/stream-clean-filter'

When running a required clean filter, we do not have to mmap the original before feeding the filter. Instead, stream the file contents directly to the filter and process its output. * sp/stream-clean-filter: sha1_file: don't convert off_t to size_t too early to avoid potential die() convert: stream from fd to required clean filter to reduce used address space copy_fd(): do not close the input file descriptor mmap_limit: introduce GIT_MMAP_LIMIT to allow testing expected mmap size memory_limit: use git_env_ulong() to parse GIT_ALLOC_LIMIT config.c: add git_env_ulong() to parse environment variable convert: drop arguments other than 'path' from would_convert_to_git()