Merge branch 'km/bsd-shells'

Portability fixes and workarounds for shell scripts have been added to help BSD-derived systems. * km/bsd-shells: t5528: do not fail with FreeBSD shell help.c: use SHELL_PATH instead of hard-coded "/bin/sh" git-compat-util.h: move SHELL_PATH default into header git-instaweb: use @SHELL_PATH@ instead of /bin/sh git-instaweb: allow running in a working tree subdirectory