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

git-compat-util.h

@@ -876,4 +876,8 @@ struct tm *git_gmtime_r(const time_t *, struct tm *);
 #define USE_PARENS_AROUND_GETTEXT_N 1
 #endif
 
+#ifndef SHELL_PATH
+# define SHELL_PATH "/bin/sh"
+#endif
+
 #endif