gzip: Actually build with optimizations:

In a basic test, this halves compression time
and cuts 20+% off decompression time.

app-arch/gzip/gzip-1.12.recipe

@@ -7,7 +7,7 @@ HOMEPAGE="https://www.gnu.org/software/gzip/"
 COPYRIGHT="1992-1993 Jean-loup Gailly
 	1999-2016 Free Software Foundation, Inc."
 LICENSE="GNU GPL v3"
-REVISION="1"
+REVISION="2"
 SOURCE_URI="http://ftpmirror.gnu.org/gzip/gzip-$portVersion.tar.xz"
 CHECKSUM_SHA256="ce5e03e519f637e1f814011ace35c4f87b33c0bbabeec35baf5fbd3479e91956"
 PATCHES="gzip-$portVersion.patchset"
@@ -54,7 +54,8 @@ TEST_REQUIRES="
 
 BUILD()
 {
-	AUTOCONF=: AUTOMAKE=: CFLAGS="-Wno-error" \
+	AUTOCONF=: AUTOMAKE=: \
+	CFLAGS="-O2 -Wno-error" \
 		runConfigure ./configure
 	make $jobArgs
 }