add direct mode to Program builder - close #61

build_tests/direct/c_program.rb

@@ -0,0 +1,5 @@
+build do
+  Environment.new do |env|
+    env.Program("test.exe", Rscons.glob("*.c"), direct: true)
+  end
+end

build_tests/direct/c_shared_library.rb

@@ -0,0 +1,7 @@
+build do
+  Environment.new do |env|
+    lib = env.SharedLibrary("mylib", ["two.c", "three.c"], direct: true)
+    program = env.Program("test.exe", "main.c", "LIBS" => ["mylib"], "LIBPATH" => ["."])
+    env.depends(program, lib)
+  end
+end

build_tests/direct/main.c

@@ -0,0 +1,7 @@
+#include "two.h"
+
+int main(int argc, char * argv[])
+{
+    two();
+    return 0;
+}

build_tests/direct/three.c

@@ -0,0 +1,7 @@
+#include "three.h"
+#include <stdio.h>
+
+void three(void)
+{
+    printf("three\n");
+}

build_tests/direct/three.h

@@ -0,0 +1 @@
+void three(void);

build_tests/direct/two.c

@@ -0,0 +1,7 @@
+#include "two.h"
+#include "three.h"
+
+void two(void)
+{
+    three();
+}

build_tests/direct/two.h

@@ -0,0 +1 @@
+void two(void);