Improve lit support (#3426)

This uses the same technique used in llvm-lit to enable
running on in-tree tests with out-of-tree builds.

So you can run something like this:

  ../binaryen-out/bin/binaryen-lit test/lit/

1 files changed, 33 insertions, 0 deletions

diff --git a/scripts/binaryen-lit.in b/scripts/binaryen-lit.in
new file mode 100755
index 000000000..f26540bc3
--- /dev/null
+++ b/scripts/binaryen-lit.in
@@ -0,0 +1,33 @@
+#!/usr/bin/env python3
+#
+# Copyright 2020 WebAssembly Community Group participants
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+from lit.main import main
+
+# A simple wrapper around `lit` test running.   Loosely based on
+# llvm's llvm-lit script
+
+builtin_parameters = {
+    'config_map': {
+        os.path.normcase(os.path.normpath('@CMAKE_SOURCE_DIR@/test/lit/lit.cfg.py')):
+        os.path.normcase(os.path.normpath('@CMAKE_BINARY_DIR@/test/lit/lit.site.cfg.py'))
+    }
+}
+
+print(builtin_parameters)
+
+if __name__ == '__main__':
+    main(builtin_parameters)