SF #665913, Fix mmap module core dump with unix

Closing an mmap'ed file (calling munmap) twice on Solaris caused a core dump.

Will backport.

Lib/test/test_mmap.py

@@ -297,6 +297,24 @@ def test_both():
         except OSError:
             pass
 
+    # make sure a double close doesn't crash on Solaris (Bug# 665913)
+    f = open(TESTFN, 'w+')
+
+    try:    # unlink TESTFN no matter what
+        f.write(2**24 * 'a') # Arbitrary character
+        f.close()
+
+        f = open(TESTFN)
+        mf = mmap.mmap(f.fileno(), 2**24, access=mmap.ACCESS_READ)
+        mf.close()
+        mf.close()
+        f.close()
+
+    finally:
+        try:
+            os.unlink(TESTFN)
+        except OSError:
+            pass
 
 
     print ' Test passed'

Modules/mmapmodule.c

@@ -141,8 +141,10 @@ mmap_close_method(mmap_object *self, PyObject *args)
 #endif /* MS_WINDOWS */
 
 #ifdef UNIX
+	if (self->data != NULL) {
 		munmap(self->data, self->size);
 		self->data = NULL;
+	}
 #endif
 
 	Py_INCREF (Py_None);