install_headers: do not exit if unifdef "fails", it's ok

extra/scripts/install_headers.sh

@@ -42,7 +42,10 @@ while read -r filename; do
 	if test -d "$1/$filename"; then
 		mkdir -p "$2/$filename" 2>/dev/null
 	else
-		"$top_builddir/extra/scripts/unifdef" -UUCLIBC_INTERNAL "$1/$filename" >"$2/$filename" || exit
+		# NB: unifdef exits with 1 if output is not
+		# exactly the same as input. That's ok.
+		# Do not abort the script if unifdef "fails"!
+		"$top_builddir/extra/scripts/unifdef" -UUCLIBC_INTERNAL "$1/$filename" >"$2/$filename"
 	fi
 done
 )