xbps-src: introduce XBPS_STATEDIR to store state files, logs and others.

XBPS_STATEDIR is created in XBPS_BUILDDIR/.xbps-${sourcepkg}-${version}
and contains logs and state files for all phases, as well as wrappers.

We can now inspect the output from all hooks.

xbps-src

@@ -266,7 +266,7 @@ install_bbootstrap() {
 masterdir_zap() {
     for f in bin boot builddir destdir dev etc home lib lib32 lib64 mnt \
         opt proc root run sbin sys tmp usr var host media xbps \
-        xbps-packages void-packages .xbps_chroot_init; do
+        void-packages .xbps_chroot_init; do
         if [ -d "$XBPS_MASTERDIR/$f" ]; then
             echo "Removing directory $XBPS_MASTERDIR/$f ..."
             rm -rf $XBPS_MASTERDIR/$f
@@ -559,6 +559,7 @@ case "$XBPS_TARGET" in
             if [ -n "$CHROOT_READY" -a -z "$IN_CHROOT" ]; then
                 chroot_handler $XBPS_TARGET $XBPS_TARGET_PKG || exit $?
             else
+                [ -d $XBPS_STATEDIR ] && rm -rf $XBPS_STATEDIR
                 remove_pkg_wrksrc $wrksrc
                 if declare -f do_clean >/dev/null; then
                     run_func do_clean