add experimental support for an alternate shell for service scripts

This is for #288.

NEWS.md

@@ -4,6 +4,13 @@ OpenRC NEWS
 This file will contain a list of notable changes for each release. Note
 the information in this file is in reverse order.
 
+## OpenRC 0.41.
+
+This version adds an experimental build time switch to allow setting the
+default shell to use for service scripts.
+By default, this is set to /bin/sh if it is changed, the new shell must
+be able to understand posix-compatible syntax.
+
 ## OpenRC 0.40
 
 In this version, the keymaps and termencoding services on Linux needed

README.md

@@ -38,6 +38,7 @@ PKG_PREFIX=/usr/pkg
 LOCAL_PREFIX=/usr/local
 PREFIX=/usr/local
 BRANDING=\"Gentoo/$(uname -s)\"
+SH=/bin/sh
 ```
 
 ## Notes

mk/scripts.mk

@@ -19,7 +19,7 @@ _PKG_SED:=		$(shell ${_PKG_SED_SH})
 _LCL_SED_SH=		if test "${PREFIX}" = "${LOCAL_PREFIX}"; then echo "-e 's:@LOCAL_PREFIX@::g'"; else echo "-e 's:@LOCAL_PREFIX@:${LOCAL_PREFIX}:g'"; fi
 _LCL_SED:=		$(shell ${_LCL_SED_SH})
 
-SED_REPLACE=		-e 's:@LIB@:${LIBNAME}:g' -e 's:@SYSCONFDIR@:${SYSCONFDIR}:g' -e 's:@LIBEXECDIR@:${LIBEXECDIR}:g' -e 's:@PREFIX@:${PREFIX}:g' -e 's:@BINDIR@:${BINDIR}:g' -e 's:@SBINDIR@:${SBINDIR}:g' ${_PKG_SED} ${_LCL_SED}
+SED_REPLACE=		-e 's:@SHELL@:${SH}:' -e 's:@LIB@:${LIBNAME}:g' -e 's:@SYSCONFDIR@:${SYSCONFDIR}:g' -e 's:@LIBEXECDIR@:${LIBEXECDIR}:g' -e 's:@PREFIX@:${PREFIX}:g' -e 's:@BINDIR@:${BINDIR}:g' -e 's:@SBINDIR@:${SBINDIR}:g' ${_PKG_SED} ${_LCL_SED}
 
 # Tweak our shell scripts
 %.sh: %.sh.in

sh/gendepends.sh.in

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!@SHELL@
 # Shell wrapper to list our dependencies
 
 # Copyright (c) 2007-2015 The OpenRC Authors.

sh/openrc-run.sh.in

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!@SHELL@
 # Shell wrapper for openrc-run
 
 # Copyright (c) 2007-2015 The OpenRC Authors.