Revert "[clang-tidy] Switch C headers to C++ ones"

This reverts commit 0344856d65.

src/recur.cpp

@@ -30,13 +30,13 @@
 #include <fstream>
 #include <sstream>
 #include <sys/types.h>
-#include <cinttypes>
-#include <cstdio>
-#include <cstring>
+#include <inttypes.h>
+#include <stdio.h>
+#include <string.h>
 #include <unistd.h>
-#include <cstdlib>
+#include <stdlib.h>
 #include <pwd.h>
-#include <ctime>
+#include <time.h>
 #include <Context.h>
 #include <Lexer.h>
 #include <Datetime.h>