Merge branch 'jk/size-t'

Code clean-up to use size_t/ssize_t when they are the right type.

* jk/size-t:
strbuf_humanise: use unsigned variables
pass st.st_size as hint for strbuf_readlink()
strbuf_readlink: use ssize_t
strbuf: use size_t for length in intermediate variables
reencode_string: use size_t for string lengths
reencode_string: use st_add/st_mult helpers

diff --cc convert.c
Simple merge

diff --cc pretty.c
Simple merge

diff --cc refs/files-backend.c
Simple merge

diff --cc strbuf.c
Simple merge

diff --cc utf8.c
Simple merge