Define internal function mythreadname() -- revised

This new function returns the name of the calling thread; works for both
 cygthreads and pthreads.  All calls to cygthread::name(/*void*/) replaced
 by calls to mythreadname(/*void*/).

winsup/cygwin/exceptions.cc

@@ -200,7 +200,7 @@ cygwin_exception::dump_exception ()
   small_printf ("r14=%016X r15=%016X\r\n", ctx->R14, ctx->R15);
   small_printf ("rbp=%016X rsp=%016X\r\n", ctx->Rbp, ctx->Rsp);
   small_printf ("program=%W, pid %u, thread %s\r\n",
-		myself->progname, myself->pid, cygthread::name ());
+		myself->progname, myself->pid, mythreadname ());
 #else
   if (exception_name)
     small_printf ("Exception: %s at eip=%08x\r\n", exception_name, ctx->Eip);
@@ -210,7 +210,7 @@ cygwin_exception::dump_exception ()
 		ctx->Eax, ctx->Ebx, ctx->Ecx, ctx->Edx, ctx->Esi, ctx->Edi);
   small_printf ("ebp=%08x esp=%08x program=%W, pid %u, thread %s\r\n",
 		ctx->Ebp, ctx->Esp, myself->progname, myself->pid,
-		cygthread::name ());
+		mythreadname ());
 #endif
   small_printf ("cs=%04x ds=%04x es=%04x fs=%04x gs=%04x ss=%04x\r\n",
 		ctx->SegCs, ctx->SegDs, ctx->SegEs, ctx->SegFs,

winsup/cygwin/fhandler_tty.cc

@@ -106,7 +106,7 @@ fhandler_pty_common::__acquire_output_mutex (const char *fn, int ln,
 #else
       ostack[osi].fn = fn;
       ostack[osi].ln = ln;
-      ostack[osi].tname = cygthread::name ();
+      ostack[osi].tname = mythreadname ();
       termios_printf ("acquired for %s:%d, osi %d", fn, ln, osi);
       osi++;
 #endif

winsup/cygwin/strace.cc

@@ -138,7 +138,7 @@ strace::vsprntf (char *buf, const char *func, const char *infmt, va_list ap)
   char fmt[80];
   static NO_COPY bool nonewline = false;
   DWORD err = GetLastError ();
-  const char *tn = cygthread::name ();
+  const char *tn = mythreadname ();
 
   int microsec = microseconds ();
   lmicrosec = microsec;

winsup/cygwin/thread.cc

@@ -2682,6 +2682,20 @@ pthread_setname_np (pthread_t thread, const char *name)
   return 0;
 }
 
+/* Returns running thread's name; works for both cygthreads and pthreads */
+char *
+mythreadname (void)
+{
+  char *result = (char *) cygthread::name ();
+
+  if (result == _my_tls.locals.unknown_thread_name)
+    {
+      result[0] = '\0';
+      pthread_getname_np (pthread_self (), result, (size_t) THRNAMELEN);
+    }
+
+  return result;
+}
 #undef THRNAMELEN
 
 /* provided for source level compatability.

winsup/cygwin/thread.h

@@ -17,6 +17,9 @@ details. */
 /* resource.cc */
 extern size_t get_rlimit_stack (void);
 
+/* thread.cc */
+char *mythreadname (void);
+
 #include <pthread.h>
 #include <limits.h>
 #include "security.h"