Merge branch 'js/mingw-fallouts'

* js/mingw-fallouts:
  fetch-pack: Prepare for a side-band demultiplexer in a thread.
  rehabilitate some t5302 tests on 32-bit off_t machines
  Allow ETC_GITCONFIG to be a relative path.
  Introduce git_etc_gitconfig() that encapsulates access of ETC_GITCONFIG.
  Allow a relative builtin template directory.
  Close files opened by lock_file() before unlinking.
  builtin run_command: do not exit with -1.
  Move #include <sys/select.h> and <sys/ioctl.h> to git-compat-util.h.
  Use is_absolute_path() in sha1_file.c.
  Skip t3902-quoted.sh if the file system does not support funny names.
  t5302-pack-index: Skip tests of 64-bit offsets if necessary.
  t7501-commit.sh: Not all seds understand option -i
  t5300-pack-object.sh: Split the big verify-pack test into smaller parts.

diff --cc Makefile
Simple merge

diff --cc git-compat-util.h
Simple merge

diff --cc git.c
Simple merge

diff --cc t/t7501-commit.sh
index 9dba104b1f8bf9125f1a947a2fd115b684a94095,31a6f63399a97902e493c453a3f3117bc44ef2f7..31a6f63399a97902e493c453a3f3117bc44ef2f7
mode 100755,100644..100755
--- 1/t/t7501-commit.sh
--- 2/t/t7501-commit.sh
+++ b/t/t7501-commit.sh