mkinitcpio: Allow building an image without modules

The '-k none' switch prevents mkinitcpio from adding modules to the
image and keeps it from bailing out when it cannot find any.

functions

@@ -351,6 +351,8 @@ add_module() {
     local module= path= deps= field= value= firmware=()
     local ign_errors=0
 
+    [[ $KERNELVERSION == none ]] && return 0
+
     if [[ $1 = *\? ]]; then
         ign_errors=1
         set -- "${1%?}"
@@ -661,7 +663,7 @@ initialize_buildroot() {
     printf '%s' "$version" >"$buildroot/VERSION"
 
     # kernel module dir
-    install -dm755 "$buildroot/usr/lib/modules/$kernver/kernel"
+    [[ $kernver != none ]] && install -dm755 "$buildroot/usr/lib/modules/$kernver/kernel"
 
     # mount tables
     ln -s /proc/self/mounts "$buildroot/etc/mtab"
@@ -738,6 +740,8 @@ install_modules() {
     local m moduledest=$BUILDROOT/lib/modules/$KERNELVERSION
     local -a xz_comp gz_comp
 
+    [[ $KERNELVERSION == none ]] && return 0
+
     if (( $# == 0 )); then
         warning "No modules were added to the image. This is probably not what you want."
         return 0

install/autodetect

@@ -4,6 +4,8 @@ build() {
     local m=
     local -a md_devs mods
 
+    [[ $KERNELVERSION == none ]] && return 0
+
     add_if_avail() {
         local r= resolved=()
 

man/mkinitcpio.8.txt

@@ -49,7 +49,8 @@ Options
 
 *-k, \--kernel* 'kernelversion'::
 	Use 'kernelversion', instead of the current running kernel. This may be a
-	path to a kernel image or a specific kernel version.
+	path to a kernel image, a specific kernel version or the special keyword
+	'none'. In the latter case, no kernel modules are added to the image.
 
 *-L, \--listhooks*::
 	List all available hooks.

mkinitcpio

@@ -417,7 +417,7 @@ fi
 
 KERNELVERSION=$(resolve_kernver "$_optkver") || cleanup 1
 _d_kmoduledir=$_optmoduleroot/lib/modules/$KERNELVERSION
-[[ -d $_d_kmoduledir ]] || die "'$_d_kmoduledir' is not a valid kernel module directory"
+[[ $KERNELVERSION == none || -d $_d_kmoduledir ]] || die "'$_d_kmoduledir' is not a valid kernel module directory"
 
 _d_workdir=$(initialize_buildroot "$KERNELVERSION" $_opttargetdir) || cleanup 1
 BUILDROOT=${_opttargetdir:-$_d_workdir/root}