execute all build tests in the top-level rake context instead of spawning subprocesses

build_tests/build_dir/build.rb

@@ -1,5 +0,0 @@
-Rscons::Environment.new do |env|
-  env.append('CPPPATH' => Dir['src/**/*/'])
-  env.build_dir(%r{^src/([^/]+)/}, 'build_\\1/')
-  env.Program('build_dir', Dir['src/**/*.c'])
-end

build_tests/build_dir/tweaker_build.rb

@@ -1,12 +0,0 @@
-Rscons::Environment.new do |env|
-  env.append('CPPPATH' => Dir['src/**/*/'])
-  env.build_dir(%r{^src/([^/]+)/}, 'build_\\1/')
-  env.add_tweaker do |build_op|
-    if build_op[:target] =~ %r{build_one/.*\.o}
-      build_op[:vars]["CFLAGS"] << "-O1"
-    elsif build_op[:target] =~ %r{build_two/.*\.o}
-      build_op[:vars]["CFLAGS"] << "-O2"
-    end
-  end
-  env.Program('tweaker', Dir['src/**/*.c'])
-end