add support for building D sources (defaulting to gdc)

lib/rscons/builders/object.rb

@@ -28,6 +28,12 @@ module Rscons
         'CXXSUFFIX' => '.cc',
         'CXXDEPGEN' => ['-MMD', '-MF', '$_DEPFILE'],
         'CXXCOM' =>['$CXX', '-c', '-o', '$_TARGET', '$CXXDEPGEN', '-I$[CPPPATH]', '$CPPFLAGS', '$CXXFLAGS', '$_SOURCES'],
+
+        'DC' => 'gdc',
+        'DFLAGS' => [],
+        'DSUFFIX' => '.d',
+        'D_IMPORT_PATH' => [],
+        'DCCOM' => ['$DC', '-c', '-o', '$_TARGET', '-I$[D_IMPORT_PATH]', '$DFLAGS', '$_SOURCES'],
       }
     end
 
@@ -35,7 +41,8 @@ module Rscons
       target.has_suffix?(env['OBJSUFFIX']) and (
         source.has_suffix?(env['ASSUFFIX']) or
         source.has_suffix?(env['CSUFFIX']) or
-        source.has_suffix?(env['CXXSUFFIX']))
+        source.has_suffix?(env['CXXSUFFIX']) or
+        source.has_suffix?(env['DSUFFIX']))
     end
 
     def run(target, sources, cache, env, vars = {})
@@ -50,6 +57,8 @@ module Rscons
                      'CC'
                    elsif sources.first.has_suffix?(env['CXXSUFFIX'])
                      'CXX'
+                   elsif sources.first.has_suffix?(env['DSUFFIX'])
+                     'DC'
                    else
                      raise "Error: unknown input file type: #{sources.first.inspect}"
                    end

lib/rscons/builders/program.rb

@@ -18,14 +18,19 @@ module Rscons
       # build sources to linkable objects
       objects = env.build_sources(sources, [env['OBJSUFFIX'], env['LIBSUFFIX']].flatten, cache, vars)
       if objects
-        use_cxx = sources.map do |s|
-          s.has_suffix?(env['CXXSUFFIX'])
-        end.any?
-        ld_alt = use_cxx ? env['CXX'] : env['CC']
+        ld = if env["LD"]
+               env["LD"]
+             elsif sources.find {|s| s.has_suffix?(env["DSUFFIX"])}
+               env["DC"]
+             elsif sources.find {|s| s.has_suffix?(env["CXXSUFFIX"])}
+               env["CXX"]
+             else
+               env["CC"]
+             end
         vars = vars.merge({
           '_TARGET' => target,
           '_SOURCES' => objects,
-          'LD' => env['LD'] || ld_alt,
+          'LD' => ld,
         })
         command = env.build_command(env['LDCOM'], vars)
         standard_build("LD #{target}", target, command, objects, env, cache)