Remove a ton of public reexports

Remove most of the public reexports mentioned in #19253

These are all leftovers from the enum namespacing transition

In particular:

* src/libstd/num/strconv.rs
 * ExponentFormat
 * SignificantDigits
 * SignFormat
* src/libstd/path/windows.rs
 * PathPrefix
* src/libstd/sys/windows/timer.rs
 * Req
* src/libcollections/str.rs
 * MaybeOwned
* src/libstd/collections/hash/map.rs
 * Entry
* src/libstd/collections/hash/table.rs
 * BucketState
* src/libstd/dynamic_lib.rs
 * Rtld
* src/libstd/io/net/ip.rs
 * IpAddr
* src/libstd/os.rs
 * MemoryMapKind
 * MapOption
 * MapError
* src/libstd/sys/common/net.rs
 * SocketStatus
 * InAddr
* src/libstd/sys/unix/timer.rs
 * Req

[breaking-change]

2 files changed, 2 insertions, 2 deletions

diff --git a/src/libsyntax/ext/mtwt.rs b/src/libsyntax/ext/mtwt.rs
index ae979020bc7..f0392912878 100644
--- a/src/libsyntax/ext/mtwt.rs
+++ b/src/libsyntax/ext/mtwt.rs
@@ -21,7 +21,7 @@ use ast::{Ident, Mrk, Name, SyntaxContext};
 
 use std::cell::RefCell;
 use std::collections::HashMap;
-use std::collections::hash_map::{Occupied, Vacant};
+use std::collections::hash_map::Entry::{Occupied, Vacant};
 
 /// The SCTable contains a table of SyntaxContext_'s. It
 /// represents a flattened tree structure, to avoid having
diff --git a/src/libsyntax/ext/tt/macro_parser.rs b/src/libsyntax/ext/tt/macro_parser.rs
index 4785fe37293..bc639c32380 100644
--- a/src/libsyntax/ext/tt/macro_parser.rs
+++ b/src/libsyntax/ext/tt/macro_parser.rs
@@ -98,7 +98,7 @@ use ptr::P;
 use std::mem;
 use std::rc::Rc;
 use std::collections::HashMap;
-use std::collections::hash_map::{Vacant, Occupied};
+use std::collections::hash_map::Entry::{Vacant, Occupied};
 
 // To avoid costly uniqueness checks, we require that `MatchSeq` always has
 // a nonempty body.