main/unbound: build with LTO

unbound: 3016 KiB -> 2056 KiB
unbound-libs: 932 KiB -> 812 KiB

This aport doesn't provide static libraries, so we can safely
build with LTO.

main/unbound/APKBUILD

@@ -4,7 +4,7 @@
 # Maintainer: Jakub Jirutka <jakub@jirutka.cz>
 pkgname=unbound
 pkgver=1.16.0
-pkgrel=0
+pkgrel=1
 pkgdesc="Unbound is a validating, recursive, and caching DNS resolver"
 url="https://nlnetlabs.nl/projects/unbound/about/"
 arch="all"
@@ -56,6 +56,9 @@ source="https://unbound.net/downloads/unbound-$pkgver.tar.gz
 #     - CVE-2019-16866
 
 build() {
+	export CFLAGS="$CFLAGS -flto"
+	export LDFLAGS="$LDFLAGS -flto"
+
 	PYTHON_VERSION=3 ./configure \
 		--build="$CBUILD" \
 		--host="$CHOST" \