Add XFreeThreads function.

include/X11/Xlib.h

@@ -1735,6 +1735,10 @@ extern Status XInitThreads(
     void
 );
 
+extern Status XFreeThreads(
+    void
+);
+
 extern void XLockDisplay(
     Display*		/* display */
 );

man/XInitThreads.man

@@ -52,6 +52,8 @@ XInitThreads, XLockDisplay, XUnlockDisplay \- multi-threading support
 .HP
 Status XInitThreads\^(void);
 .HP
+Status XFreeThreads\^(void);
+.HP
 void XLockDisplay\^(\^Display *\fIdisplay\fP\^);
 .HP
 void XUnlockDisplay\^(\^Display *\fIdisplay\fP\^);
@@ -76,7 +78,11 @@ are protected by some other access mechanism (for example,
 a mutual exclusion lock in a toolkit or through explicit client
 programming), Xlib thread initialization is not required.
 It is recommended that single-threaded programs not call this function.
-
+.LP
+The
+.B XFreeThreads
+function frees the memory allocated by
+.BR XInitThreads .
 .LP
 The
 .B XLockDisplay

src/globals.c

@@ -105,4 +105,10 @@ xlib_ctor(void)
 {
     XInitThreads();
 }
+
+__attribute__((destructor)) static void
+xlib_dtor(void)
+{
+    XFreeThreads();
+}
 #endif

src/locking.c

@@ -673,9 +673,32 @@ Status XInitThreads(void)
     return 1;
 }
 
+Status XFreeThreads(void)
+{
+    if (global_lock.lock != NULL) {
+	xmutex_free(global_lock.lock);
+	global_lock.lock = NULL;
+    }
+    if (i18n_lock.lock != NULL) {
+	xmutex_free(i18n_lock.lock);
+	i18n_lock.lock = NULL;
+    }
+    if (conv_lock.lock != NULL) {
+	xmutex_free(conv_lock.lock);
+	conv_lock.lock = NULL;
+    }
+
+    return 1;
+}
+
 #else /* XTHREADS */
 Status XInitThreads(void)
 {
     return 0;
 }
+
+Status XFreeThreads(void)
+{
+    return 0;
+}
 #endif /* XTHREADS */