wip for precompile phase for D

build_tests/d/Rsconscript

@@ -3,5 +3,6 @@ configure do
 end
 
 env(echo: :command) do |env|
-  env.Program("hello-d.exe", glob("*.d"))
+  env["D_IMPORT_PATH"] << "src"
+  env.Program("hello-d.exe", glob("src/*.d"))
 end

build_tests/d/build-ldc2.rb

@@ -3,5 +3,6 @@ configure do
 end
 
 env(echo: :command) do |env|
-  env.Program("hello-d.exe", glob("*.d"))
+  env["D_IMPORT_PATH"] << "src"
+  env.Program("hello-d.exe", glob("src/*.d"))
 end

build_tests/d/link_objects.rb

@@ -1,5 +1,6 @@
 env(echo: :command) do |env|
-  env.Object("main.o", "main.d")
-  env.Object("mod.o", "mod.d")
+  env["LD_LIBRARY_PATH"] << "src"
+  env.Object("main.o", "src/main.d")
+  env.Object("mod.o", "src/mod.d")
   env.Program("hello-d.exe", ["main.o", "mod.o"])
 end