Introduce "broken" var to skip building broken packages; make "nocross" not error out.

- broken var simply exits (without error) and skips building a pkg.
- nocross var now simply exits without an error, to make buildbot continue building pkgs.

common/environment/setup/sourcepkg.sh

@@ -3,7 +3,7 @@
 
 ## VARIABLES
 unset -v pkgname version revision short_desc homepage license maintainer
-unset -v only_for_archs distfiles checksum build_style nonfree nocross
+unset -v only_for_archs distfiles checksum build_style nonfree nocross broken
 unset -v configure_script configure_args wrksrc build_wrksrc create_wrksrc
 unset -v make_cmd make_build_args make_install_args make_build_target make_install_target python_versions
 unset -v patch_args disable_parallel_build keep_libtool_archives

common/xbps-src/shutils/common.sh

@@ -389,7 +389,11 @@ setup_pkg() {
     fi
 
     if [ "$cross" -a "$nocross" ]; then
-        msg_error "$pkgver: cannot be cross compiled, exiting...\n"
+        msg_red "$pkgver: cannot be cross compiled, exiting...\n"
+        exit 0
+    elif [ "$broken" ]; then
+        msg_red "$pkgver: cannot be built, it's currently broken; exiting...\n"
+        exit 0
     fi
 }