comments, and change how --verbose prints

src/sys.cc

 	if (global::verbose) {
 		for (size_t i = 0; i < args.size(); ++i) {
 			if (i == 0) {
-				fprintf(stderr, "%s", args[i]);
+				fprintf(stderr, "  %s", args[i]);
 			} else {
 				fprintf(stderr, " %s", args[i]);
 			}

src/toolchain.cc

 		argv.push_back(pkg.c_str());
 	}
 
+	// Execute $(PKG_CONFIG) --cflags $(PKGS)
 	std::string output;
 	sys::execute(argv, &output);
 	parseWhitespaceSeparated(output, flags);
 		argv.push_back(pkg.c_str());
 	}
 
+	// Execute $(PKG_CONFIG) --libs $(PKGS)
 	std::string output;
 	sys::execute(argv, &output);
 	parseWhitespaceSeparated(output, flags);
 	}
 
 	argv.push_back("-MM");
-	argv.push_back("-c");
 	argv.push_back(sourcePath.c_str());
+
+	// Execute $(CC) $(flags) -MM $<
 	std::string output;
 	sys::execute(argv, &output);
 
 	std::string destDir = outDir + "/" + srcDir;
 	std::string destPath = destDir + "/" + name + ".o";
 
+	// Ensure the output directory actually exists
 	sys::mkdirp(outDir);
 
 	std::vector<const char *> argv;
 	argv.push_back(destPath.c_str());
 	argv.push_back("-c");
 	argv.push_back(sourcePath.c_str());
+
+	// Execute $(CC) $(flags) -o $@ -c $<
 	sys::execute(argv, nullptr);
 }