quickpkg: Fix incorrect BINPKG_COMPRESS_FLAGS split.

Bug: https://bugs.gentoo.org/857933
Signed-off-by: Sheng Yu <syu.os@protonmail.com>
Closes: https://github.com/gentoo/portage/pull/857
Signed-off-by: Sam James <sam@gentoo.org>
diff --git a/NEWS b/NEWS
index 129416f..6345314 100644
--- a/NEWS
+++ b/NEWS
@@ -16,6 +16,8 @@
   started to show on every emerge, but is harmless and left over
   from many years ago). Bug #858407.
 
+* quickpkg: Fix quoting/splitting of BINPKG_COMPRESS_FLAGS arguments. Bug #857933.
+
 * estrip: fix double prefix (regression from "don't call estrip twice" fix
   in 3.0.31). Bug #858818.
 
diff --git a/bin/quickpkg b/bin/quickpkg
index b4ad433..773c1c0 100755
--- a/bin/quickpkg
+++ b/bin/quickpkg
@@ -167,10 +167,7 @@
                         % (binpkg_compression, missing_package)
                     )
                     return 1
-                cmd = [
-                    varexpand(x, mydict=settings)
-                    for x in shlex_split(compression["compress"])
-                ]
+                cmd = shlex_split(varexpand(compression["compress"], mydict=settings))
                 # Filter empty elements that make Popen fail
                 cmd = [x for x in cmd if x != ""]
                 with open(binpkg_tmpfile, "wb") as fobj: