abuild: do not try to strip standalone elf images

Guile uses ELF is internal object format, and creates them as
"no machine" and "standlone" OSABI. Scanelf supports printing
OSABI, so use that to filter these out.
See: https://github.com/alpinelinux/aports/pull/1714

This also removes unneccessary 'sed' from the pipeline as it's
simple to read each field outputted by scanelf.

abuild.in

@@ -2142,9 +2142,9 @@ stripbin() {
 	esac
 
 	msg "Stripping binaries"
-	scanelf --recursive --nobanner --etype "ET_DYN,ET_EXEC" . \
-		| sed -e 's:^ET_DYN ::' -e 's:^ET_EXEC ::' \
-		| while read filename; do
+	scanelf --recursive --nobanner --osabi --etype "ET_DYN,ET_EXEC" . \
+		| while read type osabi filename; do
+		[ "$osabi" != "STANDALONE" ] || continue
 		local XATTR=$(getfattr --match="" --dump "${filename}")
 		"${stripcmd}" "${filename}"
 		if [ -n "$XATTR" ]; then