* globals.cc (__isthreaded): New global variable. Explain what it's

used for.
	* miscfuncs.cc (thread_wrapper): Set __isthreaded to 1 here.

winsup/cygwin/globals.cc

@@ -75,6 +75,13 @@ bool detect_bloda = false;
 
 bool NO_COPY in_forkee;
 
+/* Taken from BSD libc:
+   This variable is zero until a process has created a pthread.  It is used
+   to avoid calling locking functions in libc when they are not required.
+   Note that this is moderately dangerous.  Do not rely on it if the public
+   API is also used from a non-pthread thread like the signal thread. */
+int NO_COPY __isthreaded = 0;
+
 int __argc_safe;
 int __argc;
 char **__argv;