[c++0x] remove std::lock_error

[Jonathan Wakely <jwakely dot gcc at gmail dot com>]

std::lock_error was removed from the C++0x draft between n2691 and
n2723, it's unused in libstdc++ except for
testsuite/30_threads/headers/mutex/types_std_c++0x.cc but as its
exported it needs to be kept for binary compatibility.

        * include/std/mutex: Move std::lock_error to ...
        * src/mutex.cc: Here.
        * testsuite/30_threads/headers/mutex/types_std_c++0x.cc: Add checks
        for lock types and remove std::lock_error check.

tested x86_64 linux, is this OK for trunk?

Index: include/std/mutex
===================================================================
--- include/std/mutex	(revision 147496)
+++ include/std/mutex	(working copy)
@@ -386,18 +386,6 @@ namespace std
   extern const try_to_lock_t	try_to_lock;
   extern const adopt_lock_t	adopt_lock;
 
-  /** 
-   *  @brief Thrown to indicate errors with lock operations.
-   *
-   *  @ingroup exceptions
-   */
-  class lock_error : public exception
-  {
-  public:
-    virtual const char*
-    _GLIBCXX_CONST what() const throw();
-  };
-
   /// @brief  Scoped lock idiom.
   // Acquire the mutex here with a constructor call, then release with
   // the destructor call in accordance with RAII style.
Index: src/mutex.cc
===================================================================
--- src/mutex.cc	(revision 147496)
+++ src/mutex.cc	(working copy)
@@ -43,6 +43,18 @@ namespace std
   const try_to_lock_t try_to_lock = try_to_lock_t();
   const adopt_lock_t adopt_lock = adopt_lock_t();
 
+  /** 
+   *  @brief Removed from C++0x draft, preserved for ABI reasons
+   *
+   *  @ingroup exceptions
+   */
+  class lock_error : public exception
+  {
+  public:
+    virtual const char*
+    _GLIBCXX_CONST what() const throw();
+  };
+
   const char*
   lock_error::what() const throw()
   { return "std::lock_error"; }
Index: testsuite/30_threads/headers/mutex/types_std_c++0x.cc
===================================================================
--- testsuite/30_threads/headers/mutex/types_std_c++0x.cc	(revision 147496)
+++ testsuite/30_threads/headers/mutex/types_std_c++0x.cc	(working copy)
@@ -35,7 +35,8 @@ void test01()
   using std::try_to_lock;
   using std::adopt_lock;
 
-  typedef std::lock_error error_t;
+  typedef std::lock_guard<mutext_t> lock_t;
+  typedef std::unique_lock<rmutext_t> ulock_t;
 
   typedef std::once_flag once_t;
 }