Revert "package/pkg-generic.mk: create directories upfront in the configure step"

This _partially_ reverts commit 2dbb0660fb.

Indeed, before 2dbb0660fb, the per-package ../host/ directory was
explicitly created right before it was populated. With 2dbb0660fb, it
is now created only at the beginning of the configure step.

However, some packages may have download or extract host dependencies,
and when we are trying to rsync them, the destination .../host/
directory does not yet exist at the download or extract steps, thus the
build fails. E.g., with wget which needs host-lzip if the system does
not have it yet:

    rsync -a --link-dest=/home/ymorin/dev/buildroot/O/per-package/host-lzip/host/ /home/ymorin/dev/buildroot/O/per-package/host-lzip/host/ /home/ymorin/dev/buildroot/O/per-package/wget/host
    rsync: mkdir "/home/ymorin/dev/buildroot/O/per-package/wget/host" failed: No such file or directory (2)
    rsync error: error in file IO (code 11) at main.c(682) [Receiver=3.1.3]
    make[1]: *** [package/pkg-generic.mk:170: /home/ymorin/dev/buildroot/O/build/wget-1.20.3/.stamp_extracted] Error 11

Kudos to Raphael for pin-pointing the culprit commit.

Fixes:
    http://autobuild.buildroot.org/results/4c8/4c895c7ac0a635d38f5015b5df0393581ad7b508/
    and a slew of similar failures

Notes:
An alternative solution would be to move the creation of the directories
from the configure step to the download step *and* to the rsync step,
but this is not so nice in the end... Let's just ensure they are created
where needed: at the configure step, and when populating them.

Reported-by: Raphael Jacob <r.jacob2002@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/pkg-utils.mk

@@ -163,6 +163,7 @@ ifeq ($(BR2_PER_PACKAGE_DIRECTORIES),y)
 # $2: 'host' or 'target'
 # $3: destination directory
 define per-package-rsync
+	mkdir -p $(3)
 	$(foreach pkg,$(1),\
 		rsync -a --link-dest=$(PER_PACKAGE_DIR)/$(pkg)/$(2)/ \
 		$(PER_PACKAGE_DIR)/$(pkg)/$(2)/ \