refactor: modernize deprecated ipc headers

Co-authored-by: fanquake <fanquake@gmail.com>

src/ipc/capnp/protocol.cpp

@@ -16,8 +16,8 @@
 #include <mp/util.h>
 #include <util/threadnames.h>
 
-#include <assert.h>
-#include <errno.h>
+#include <cassert>
+#include <cerrno>
 #include <future>
 #include <memory>
 #include <mutex>

src/ipc/interfaces.cpp

@@ -15,10 +15,10 @@
 
 #include <cstdio>
 #include <cstdlib>
+#include <cstring>
 #include <functional>
 #include <memory>
 #include <stdexcept>
-#include <string.h>
 #include <string>
 #include <unistd.h>
 #include <utility>

src/ipc/process.cpp

@@ -13,11 +13,11 @@
 
 #include <cstdint>
 #include <cstdlib>
-#include <errno.h>
+#include <cstring>
+#include <cerrno>
 #include <exception>
 #include <iostream>
 #include <stdexcept>
-#include <string.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <unistd.h>