manually encode newlines on all printed commands

This way we group key value arguments: e.g.:

    make \
    -j 8 \
    all

instead of:

    make \
    -j \
    8 \
    all

and reach CLI nirvana, while also subtly breaking several commands due to
lack of testing.

build

@@ -76,6 +76,9 @@ name_to_component_map = {
     'qemu': Component(
         lambda arch: run_cmd(['build-qemu'], arch),
     ),
+    'qemu-user': Component(
+        lambda arch: run_cmd(['build-qemu', '--userland'], arch),
+    ),
     'userland': Component(
         lambda arch: run_cmd(['build-userland'], arch),
     ),
@@ -85,6 +88,7 @@ name_to_component_map = {
         'qemu-gem5-buildroot',
         'gem5-debug',
         'gem5-fast',
+        'qemu-user',
     ]),
     'gem5-buildroot': Component(dependencies=[
         'buildroot-gcc',