Improve searching for XXX in tidy script (rust-lang#3303)

Few places where previous version of tidy script cannot find XXX:
* inside one-line comment preceding by a few spaces;
* inside multiline comments (now it finds it if multiline comment starts
on the same line with XXX).

Change occurences of XXX found by new tidy script.

src/etc/tidy.py

@@ -65,10 +65,11 @@ def do_license_check(name, contents):
                 check_tab = False
             if line.find(linelength_flag) != -1:
                 check_linelength = False
-            if line.find("// XXX") != -1:
-                report_err("XXX is no longer necessary, use FIXME")
             if line.find("TODO") != -1:
                 report_err("TODO is deprecated; use FIXME")
+            match = re.match(r'^.*/(\*|/!?)\s*XXX', line)
+            if match:
+                report_err("XXX is no longer necessary, use FIXME")
             match = re.match(r'^.*//\s*(NOTE.*)$', line)
             if match:
                 m = match.group(1)

src/librustuv/addrinfo.rs

@@ -120,7 +120,7 @@ impl Drop for Addrinfo {
 }
 
 fn each_ai_flag(_f: |c_int, ai::Flag|) {
-    /* XXX: do we really want to support these?
+    /* FIXME: do we really want to support these?
     unsafe {
         f(uvll::rust_AI_ADDRCONFIG(), ai::AddrConfig);
         f(uvll::rust_AI_ALL(), ai::All);
@@ -150,7 +150,7 @@ pub fn accum_addrinfo(addr: &Addrinfo) -> ~[ai::Info] {
                 }
             });
 
-            /* XXX: do we really want to support these
+            /* FIXME: do we really want to support these
             let protocol = match (*addr).ai_protocol {
                 p if p == uvll::rust_IPPROTO_UDP() => Some(ai::UDP),
                 p if p == uvll::rust_IPPROTO_TCP() => Some(ai::TCP),

src/libstd/rt/local_ptr.rs

@@ -12,7 +12,7 @@
 //!
 //! The runtime will use this for storing ~Task.
 //!
-//! XXX: Add runtime checks for usage of inconsistent pointer types.
+//! FIXME: Add runtime checks for usage of inconsistent pointer types.
 //! and for overwriting an existing pointer.
 
 #![allow(dead_code)]

src/test/bench/shootout-threadring.rs

@@ -15,7 +15,7 @@ use std::os;
 fn start(n_tasks: int, token: int) {
     let (tx, mut rx) = channel();
     tx.send(token);
-    //  XXX could not get this to work with a range closure
+    //  FIXME could not get this to work with a range closure
     let mut i = 2;
     while i <= n_tasks {
         let (tx, next_rx) = channel();