Stop calling PyEval_InitThreads() In Py3.7+ (where it has become a no-op).

Cython/Compiler/ModuleNode.py

@@ -2406,11 +2406,10 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
             code.put_error_if_neg(self.pos, "_import_array()")
 
         code.putln("/*--- Threads initialization code ---*/")
-        code.putln("#if defined(__PYX_FORCE_INIT_THREADS) && __PYX_FORCE_INIT_THREADS")
-        code.putln("#ifdef WITH_THREAD /* Python build with threading support? */")
+        code.putln("#if defined(WITH_THREAD) && PY_VERSION_HEX < 0x030700F0 "
+                   "&& defined(__PYX_FORCE_INIT_THREADS) && __PYX_FORCE_INIT_THREADS")
         code.putln("PyEval_InitThreads();")
         code.putln("#endif")
-        code.putln("#endif")
 
         code.putln("/*--- Module creation code ---*/")
         self.generate_module_creation_code(env, code)

Cython/Utility/ModuleSetupCode.c

@@ -922,7 +922,7 @@ typedef struct {PyObject **p; const char *s; const Py_ssize_t n; const char* enc
 
 /////////////// InitThreads.init ///////////////
 
-#ifdef WITH_THREAD
+#if defined(WITH_THREAD) && PY_VERSION_HEX < 0x030700F0
 PyEval_InitThreads();
 #endif