commit 00f84e4cb1efc02149d9c04df79048c04351e46a
Author: CYBERDEViL <cyberdevil@notabug.org>
Date:   Sun Dec 17 01:13:47 2023 +0100

    python3.7: "Cleanup: remove deprecated PyEval_InitThreads use"
    
    Fully applied Blender upstream ref: d377b1fe762c24ee74805ea8c1f666f121399698

commit a6323887a2db1acd10bd0fd1539fb8c061efc7f3
Author: CYBERDEViL <cyberdevil@notabug.org>
Date:   Sat Dec 16 17:51:18 2023 +0100

    python3.7: "Fix PyRNA class registration w/ Python 3.7"
    
    Fully applied Blender upstream ref: 1db47a2ccd1e68994bf8140eba6cc2a26a2bc91f

diff --git a/blender-2.79b/source/blender/python/intern/bpy_interface.c b/blender-2.79b/source/blender/python/intern/bpy_interface.c
index 20cfd36..6077418 100644
--- a/blender-2.79b/source/blender/python/intern/bpy_interface.c
+++ b/blender-2.79b/source/blender/python/intern/bpy_interface.c
@@ -268,6 +268,7 @@ void BPY_python_start(int argc, const char **argv)
 
 	Py_FrozenFlag = 1;
 
+	/* Initialize Python (also acquires lock). */
 	Py_Initialize();
 
 	// PySys_SetArgv(argc, argv);  /* broken in py3, not a huge deal */
@@ -284,9 +285,7 @@ void BPY_python_start(int argc, const char **argv)
 		PySys_SetObject("argv", py_argv);
 		Py_DECREF(py_argv);
 	}
-	
-	/* Initialize thread support (also acquires lock) */
-	PyEval_InitThreads();
+
 #else
 	(void)argc;
 	(void)argv;
diff --git a/blender-2.79b/source/blender/python/intern/bpy_rna.c b/blender-2.79b/source/blender/python/intern/bpy_rna.c
index 0d3781c..832a872 100644
--- a/blender-2.79b/source/blender/python/intern/bpy_rna.c
+++ b/blender-2.79b/source/blender/python/intern/bpy_rna.c
@@ -7385,10 +7385,12 @@ static int bpy_class_validate_recursive(PointerRNA *dummyptr, StructRNA *srna, v
 		if (!(flag & PROP_REGISTER))
 			continue;
 
+		/* TODO(campbell): Use Python3.7x _PyObject_LookupAttr(), also in the macro below. */
 		identifier = RNA_property_identifier(prop);
 		item = PyObject_GetAttrString(py_class, identifier);
 
 		if (item == NULL) {
+			PyErr_Clear();
 			/* Sneaky workaround to use the class name as the bl_idname */
 
 #define     BPY_REPLACEMENT_STRING(rna_attr, py_attr)                         \
@@ -7404,6 +7406,9 @@ static int bpy_class_validate_recursive(PointerRNA *dummyptr, StructRNA *srna, v
 					}                                                         \
 					Py_DECREF(item);                                          \
 				}                                                             \
+				else {                                                        \
+					PyErr_Clear();                                            \
+				}                                                             \
 			}  /* intentionally allow else here */
 
 			if (false) {}  /* needed for macro */