Add more integration tests for SharedLibrary and backwards compatibility

build_tests/simple/bc_produces.rb

@@ -0,0 +1,28 @@
+class MyObject < Rscons::Builder
+  def produces?(target, source, env)
+    target.end_with?(".o") and source.end_with?(".xyz")
+  end
+
+  def run(target, sources, cache, env, vars)
+    cflags = env.expand_varref("${CFLAGS}", vars)
+    vars = vars.merge(
+      "CFLAGS" => cflags + %w[-x c],
+      "CSUFFIX" => ".xyz")
+    env.run_builder(env.builders["Object"], target, sources, cache, vars)
+  end
+end
+
+Rscons::Environment.new do |env|
+  env.add_builder(MyObject.new)
+  File.open("test.xyz", "w") do |fh|
+    fh.puts <<EOF
+#include <stdio.h>
+int main(int argc, char * argv[])
+{
+    printf("XYZ!\\n");
+    return 0;
+}
+EOF
+  env.Program("test", "test.xyz")
+  end
+end