testing/libiptcdata: set build/host for consistency

testing/libiptcdata/APKBUILD

@@ -18,6 +18,7 @@ _builddir=${srcdir}/${pkgname}-${pkgver}
 prepare() {
 	local i
 	cd "$_builddir"
+	update_config_sub || return 1
 	for i in $source; do
 		case $i in
 		*.patch) msg $i; patch -p1 -i "$srcdir"/$i || return 1;;
@@ -28,7 +29,11 @@ prepare() {
 
 build() {
 	cd "$_builddir"
-        ./configure --prefix=/usr || return 1
+        ./configure \
+		--build=$CBUILD \
+		--host=$CHOST \
+		--prefix=/usr \
+		|| return 1
         make || return 1
 }