Generate configure for Jemalloc.

deps/jemalloc/VERSION

@@ -0,0 +1 @@
+5.1.0-0-g0

deps/jemalloc/test/integration/cpp/basic.cpp

@@ -0,0 +1,25 @@
+#include <memory>
+#include "test/jemalloc_test.h"
+
+TEST_BEGIN(test_basic) {
+	auto foo = new long(4);
+	assert_ptr_not_null(foo, "Unexpected new[] failure");
+	delete foo;
+	// Test nullptr handling.
+	foo = nullptr;
+	delete foo;
+
+	auto bar = new long;
+	assert_ptr_not_null(bar, "Unexpected new failure");
+	delete bar;
+	// Test nullptr handling.
+	bar = nullptr;
+	delete bar;
+}
+TEST_END
+
+int
+main() {
+	return test(
+	    test_basic);
+}