community/asio: improve abuild

community/asio/APKBUILD

 # Maintainer: Natanael Copa <ncopa@alpinelinux.org>
 pkgname=asio
 pkgver=1.12.0
-_ver=${pkgver//./-}
 pkgrel=2
-pkgdesc="A cross-platform C++ library for network programming"
+pkgdesc="Cross-platform C++ library for network programming"
 url="https://think-async.com"
 arch="all"
 license="BSL-1.0"
@@ -17,7 +16,7 @@ source="http://downloads.sourceforge.net/sourceforge/asio/$pkgname-$pkgver.tar.b
 builddir="$srcdir/$pkgname-$pkgver"
 
 prepare() {
-	cd "$builddir"
+	default_prepare
 	update_config_sub
 }