recipetool/devtool: calculate source paths relative to UNPACKDIR

Now that recipes default to S in UNPACKDIR, recipetool and devtool should
do the same.

There was some discussion about changing devtool to simply setting
UNPACKDIR via bbappend to a workspace and running unpack task directly;
currently it has a bunch of convoluted path calculations, substitutions,
moving source trees around and and special casing (devtool-source.bbclass
in particular is an unpleasant hack).

This should definitely be done; but right now we can simply tweak existing
code which at least doesn't make it worse.

(From OE-Core rev: c326ca8aeb2bf0f7719e43921d10efd5dedc7b2a)

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/recipetool/create.py

@@ -735,7 +735,7 @@ def create_recipe(args):
     if srcsubdir and not args.binary:
         # (for binary packages we explicitly specify subdir= when fetching to
         # match the default value of S, so we don't need to set it in that case)
-        lines_before.append('S = "${WORKDIR}/%s"' % srcsubdir)
+        lines_before.append('S = "${UNPACKDIR}/%s"' % srcsubdir)
         lines_before.append('')
 
     if pkgarch:
@@ -839,7 +839,7 @@ def create_recipe(args):
                 line = line.replace(realpv, '${PV}')
             if pn:
                 line = line.replace(pn, '${BPN}')
-            if line == 'S = "${WORKDIR}/${BPN}-${PV}"' or 'tmp-recipetool-' in line:
+            if line == 'S = "${UNPACKDIR}/${BPN}-${PV}"' or 'tmp-recipetool-' in line:
                 skipblank = True
                 continue
         elif line.startswith('SRC_URI = '):