bpo-35059: Add Py_STATIC_INLINE() macro (GH-10093)

* Add Py_STATIC_INLINE() macro to declare a "static inline" function.
  If the compiler supports it, try to always inline the function even if no
  optimization level was specified.
* Modify pydtrace.h to use Py_STATIC_INLINE() when WITH_DTRACE is
  not defined.
* Add an unit test on Py_DECREF() to make sure that
  _Py_NegativeRefcount() reports the correct filename.
diff --git a/Include/pydtrace.h b/Include/pydtrace.h
index 037961d..cfe192f 100644
--- a/Include/pydtrace.h
+++ b/Include/pydtrace.h
@@ -25,29 +25,29 @@
 
 /* Without DTrace, compile to nothing. */
 
-static inline void PyDTrace_LINE(const char *arg0, const char *arg1, int arg2) {}
-static inline void PyDTrace_FUNCTION_ENTRY(const char *arg0, const char *arg1, int arg2)  {}
-static inline void PyDTrace_FUNCTION_RETURN(const char *arg0, const char *arg1, int arg2) {}
-static inline void PyDTrace_GC_START(int arg0) {}
-static inline void PyDTrace_GC_DONE(int arg0) {}
-static inline void PyDTrace_INSTANCE_NEW_START(int arg0) {}
-static inline void PyDTrace_INSTANCE_NEW_DONE(int arg0) {}
-static inline void PyDTrace_INSTANCE_DELETE_START(int arg0) {}
-static inline void PyDTrace_INSTANCE_DELETE_DONE(int arg0) {}
-static inline void PyDTrace_IMPORT_FIND_LOAD_START(const char *arg0) {}
-static inline void PyDTrace_IMPORT_FIND_LOAD_DONE(const char *arg0, int arg1) {}
+Py_STATIC_INLINE(void) PyDTrace_LINE(const char *arg0, const char *arg1, int arg2) {}
+Py_STATIC_INLINE(void) PyDTrace_FUNCTION_ENTRY(const char *arg0, const char *arg1, int arg2)  {}
+Py_STATIC_INLINE(void) PyDTrace_FUNCTION_RETURN(const char *arg0, const char *arg1, int arg2) {}
+Py_STATIC_INLINE(void) PyDTrace_GC_START(int arg0) {}
+Py_STATIC_INLINE(void) PyDTrace_GC_DONE(int arg0) {}
+Py_STATIC_INLINE(void) PyDTrace_INSTANCE_NEW_START(int arg0) {}
+Py_STATIC_INLINE(void) PyDTrace_INSTANCE_NEW_DONE(int arg0) {}
+Py_STATIC_INLINE(void) PyDTrace_INSTANCE_DELETE_START(int arg0) {}
+Py_STATIC_INLINE(void) PyDTrace_INSTANCE_DELETE_DONE(int arg0) {}
+Py_STATIC_INLINE(void) PyDTrace_IMPORT_FIND_LOAD_START(const char *arg0) {}
+Py_STATIC_INLINE(void) PyDTrace_IMPORT_FIND_LOAD_DONE(const char *arg0, int arg1) {}
 
-static inline int PyDTrace_LINE_ENABLED(void) { return 0; }
-static inline int PyDTrace_FUNCTION_ENTRY_ENABLED(void) { return 0; }
-static inline int PyDTrace_FUNCTION_RETURN_ENABLED(void) { return 0; }
-static inline int PyDTrace_GC_START_ENABLED(void) { return 0; }
-static inline int PyDTrace_GC_DONE_ENABLED(void) { return 0; }
-static inline int PyDTrace_INSTANCE_NEW_START_ENABLED(void) { return 0; }
-static inline int PyDTrace_INSTANCE_NEW_DONE_ENABLED(void) { return 0; }
-static inline int PyDTrace_INSTANCE_DELETE_START_ENABLED(void) { return 0; }
-static inline int PyDTrace_INSTANCE_DELETE_DONE_ENABLED(void) { return 0; }
-static inline int PyDTrace_IMPORT_FIND_LOAD_START_ENABLED(void) { return 0; }
-static inline int PyDTrace_IMPORT_FIND_LOAD_DONE_ENABLED(void) { return 0; }
+Py_STATIC_INLINE(int) PyDTrace_LINE_ENABLED(void) { return 0; }
+Py_STATIC_INLINE(int) PyDTrace_FUNCTION_ENTRY_ENABLED(void) { return 0; }
+Py_STATIC_INLINE(int) PyDTrace_FUNCTION_RETURN_ENABLED(void) { return 0; }
+Py_STATIC_INLINE(int) PyDTrace_GC_START_ENABLED(void) { return 0; }
+Py_STATIC_INLINE(int) PyDTrace_GC_DONE_ENABLED(void) { return 0; }
+Py_STATIC_INLINE(int) PyDTrace_INSTANCE_NEW_START_ENABLED(void) { return 0; }
+Py_STATIC_INLINE(int) PyDTrace_INSTANCE_NEW_DONE_ENABLED(void) { return 0; }
+Py_STATIC_INLINE(int) PyDTrace_INSTANCE_DELETE_START_ENABLED(void) { return 0; }
+Py_STATIC_INLINE(int) PyDTrace_INSTANCE_DELETE_DONE_ENABLED(void) { return 0; }
+Py_STATIC_INLINE(int) PyDTrace_IMPORT_FIND_LOAD_START_ENABLED(void) { return 0; }
+Py_STATIC_INLINE(int) PyDTrace_IMPORT_FIND_LOAD_DONE_ENABLED(void) { return 0; }
 
 #endif /* !WITH_DTRACE */