BuildSystem: using sysroot doesn't need root privileges anymore!

Sysroot is now created with fakeroot. This allows root access to be
only needed for disk image creation, since it uses loopback devices.

script/build.sh

@@ -4,6 +4,12 @@ set -e
 export BANAN_SCRIPT_DIR=$(dirname $(realpath $0))
 source $BANAN_SCRIPT_DIR/config.sh
 
+FAKEROOT_FILE="$BANAN_BUILD_DIR/fakeroot-context"
+
+run_fakeroot() {
+	fakeroot -i $FAKEROOT_FILE -s $FAKEROOT_FILE -- /bin/bash -c '$@' bash $@
+}
+
 make_build_dir () {
 	mkdir -p $BANAN_BUILD_DIR
 	cd $BANAN_BUILD_DIR
@@ -19,7 +25,7 @@ build_target () {
 		exit 1
 	fi
 	cd $BANAN_BUILD_DIR
-	ninja $1
+	run_fakeroot ninja $1
 }
 
 build_toolchain () {
@@ -39,11 +45,7 @@ build_toolchain () {
 
 create_image () {
 	build_target install-sysroot
-	if [[ "$1" == "full" ]]; then
-		$BANAN_SCRIPT_DIR/image-full.sh
-	else
-		$BANAN_SCRIPT_DIR/image.sh
-	fi
+	$BANAN_SCRIPT_DIR/image.sh "$1"
 }
 
 run_qemu () {
@@ -56,7 +58,7 @@ run_bochs () {
 	$BANAN_SCRIPT_DIR/bochs.sh $@
 }
 
-if [[ "$(uname)" == "Linux" ]]; then
+if [[ -c /dev/kvm ]]; then
 	QEMU_ACCEL="-accel kvm"
 fi