Merge branch 'ab/clang-lints' into maint-1.7.7

* ab/clang-lints:
  cast variable in call to free() in builtin/diff.c and submodule.c
  apply: get rid of useless x < 0 comparison on a size_t type

diff --cc builtin/apply.c
Simple merge

diff --cc submodule.c
Simple merge