xbps-src: added XBPS_ALLOW_RESTRICTED conf option for restricted pkgs.

Such packages should set the `restricted' var to allow building a binary package.
Note that such packages do not allow redistribution of sources and binaries,
so that it's up to the user if (s)he wants to pkg it locally.

common/xbps-src/shutils/common.sh

@@ -446,6 +446,11 @@ setup_pkg() {
         exit 2
     fi
 
+    if [ -n "$restricted" -a -z "$XBPS_ALLOW_RESTRICTED" ]; then
+        msg_red "$pkgver: does not allow redistribution of sources/binaries (restricted license).\n"
+        exit 2
+    fi
+
     export XBPS_STATEDIR="${XBPS_BUILDDIR}/.xbps-${sourcepkg}"
     export XBPS_WRAPPERDIR="${XBPS_STATEDIR}/wrappers"