Kernel/LibC: userspace malloc now uses mmap to get memory

We could remove syscalls to allocate more memory. This was not
something the kernel should have done.

libc/CMakeLists.txt

@@ -7,6 +7,7 @@ set(LIBC_SOURCES
 	ctype.cpp
 	dirent.cpp
 	fcntl.cpp
+	malloc.cpp
 	printf_impl.cpp
 	pwd.cpp
 	signal.cpp