Refactoring build system for more control of inputs

scripts/templates/target.default.j2

@@ -0,0 +1,17 @@
+builddir = $builddir/{{ target }}
+
+{% block variables %}
+{% endblock %}
+
+{% block binaries %}
+cc = clang
+cxx = clang++
+ld = clang++
+ar = ar
+nasm = nasm
+objcopy = objcopy
+{% endblock %}
+
+{% for module in modules %}
+subninja {{ module.name }}.ninja
+{% endfor %}