musl: changed to set libdir=$slibdir if $auto_prefix=1

base/musl/musl.conf

@@ -15,6 +15,11 @@
 # translate $arch for being usable with musl
 musl_arch="$( echo $arch | arch2uname )"
 
+if [ $prefix_auto == 1 ]; then
+	slibdir="/lib"
+	libdir="$slibdir"
+fi
+
 if atstage toolchain; then
 	confopt="--prefix=$base/build/$SDECFG_ID/usr \$extraconfopt"