half: Fix S = WORKDIR reference

Setting `S = ${WORKDIR}` is no longer allowed. Use the the default
setting of S and move the sources accordingly.
Compare wit OE-core commit 32cba1cc91 ("insane: Error for S == WORKDIR")

Fixes:
ERROR: <xyz>.bb: Using S = ${WORKDIR} is no longer supported

Signed-off-by: Max Krummenacher <[email protected]>

recipes-devtools/half/half_2.1.0.bb

@@ -10,7 +10,7 @@ SRC_URI = "https://sourceforge.net/projects/half/files/half/${PV}/${BP}.zip"
 SRC_URI[md5sum] = "cd28e42c77b99e4cca4f5e9fc76e0433"
 SRC_URI[sha256sum] = "ad1788afe0300fa2b02b0d1df128d857f021f92ccf7c8bddd07812685fa07a25"
 
-S = "${WORKDIR}"
+UNPACKDIR = "${S}"
 
 do_install () {
     install -d ${D}${includedir}