common/environment/setup/install.sh: add vcompletion.

Install function for installing shell completions in the appropriate
place according to the shell used.

Manual.md

@@ -337,6 +337,13 @@ The following functions are defined by `xbps-src` and can be used on any templat
 	Note that vsed will call the sed command for every regex specified against
 	every file specified, in the order that they are given.
 
+- *vcompletion()* `<file> <shell> [<command>]`
+
+	Installs shell completion from `file` for `command`, in the correct location
+	and with the appropriate filename for `shell`. If `command` isn't specified,
+	it will default to `pkgname`. The `shell` argument can be one of `bash`,
+	`fish` or `zsh`.
+
 > Shell wildcards must be properly quoted, Example: `vmove "usr/lib/*.a"`.
 
 <a id="global_vars"></a>

common/environment/setup/install.sh

@@ -13,7 +13,7 @@ _noglob_helper() {
 }
 
 # Apply _noglob to v* commands
-for cmd in vinstall vcopy vmove vmkdir vbin vman vdoc vconf vsconf vlicense vsv; do
+for cmd in vinstall vcopy vcompletion vmove vmkdir vbin vman vdoc vconf vsconf vlicense vsv; do
        alias ${cmd}="set -f; _noglob_helper _${cmd}"
 done
 
@@ -258,3 +258,31 @@ _vmkdir() {
 		install -dm${mode} ${_destdir}/${dir}
 	fi
 }
+
+_vcompletion() {
+	local file="$1" shell="$2" cmd="${3:-${pkgname}}"
+	local _bash_completion_dir=usr/share/bash-completion/completions/
+	local _fish_completion_dir=usr/share/fish/vendor_completions.d/
+	local _zsh_completion_dir=usr/share/zsh/site-functions/
+
+	if [ -z "$DESTDIR" ]; then
+		msg_red "$pkgver: vcompletion: DESTDIR unset, can't continue...\n"
+		return 1
+	fi
+
+	if [ $# -lt 2 ]; then
+		msg_red "$pkgver: vcompletion: 2 arguments expected: <file> <shell>\n"
+		return 1
+	fi
+
+	if ! [ -f "$file" ]; then
+		msg_red "$pkgver: vcompletion: file $file doesn't exist\n"
+	fi
+
+	case "$shell" in
+		bash) vinstall "$file" 0644 $_bash_completion_dir "${cmd}" ;;
+		fish) vinstall "$file" 0644 $_fish_completion_dir "${cmd}.fish" ;;
+		zsh) vinstall "$file" 0644 $_zsh_completion_dir "_${cmd}" ;;
+		*) msg_red "$pkgver: vcompletion: unknown shell ${shell}" ;;
+	esac
+}