diff --git a/make/py-defs.mk b/make/py-defs.mk
index 80503b5d..ce4504c6 100644
--- a/make/py-defs.mk
+++ b/make/py-defs.mk
@@ -27,7 +27,8 @@ PY_ALL_PY                    = $(PY_SRC_PY)
 ifneq ($(PYTHON_VERSION),3)
   PY_PYC                     = $(patsubst %.py,%.pyc,$(PY_ALL_PY))
 else
-  PY_PYC                     = $(patsubst %.py,__pycache__/%.cpython-37.pyc,$(PY_ALL_PY))
+  PY_CPYTHON_PREFIX         := $(shell $(PYTHON) -c "import sys; print('cpython-{}{}'.format(sys.version_info[0],sys.version_info[1]))")
+  PY_PYC                     = $(patsubst %.py,__pycache__/%.$(PY_CPYTHON_PREFIX).pyc,$(PY_ALL_PY))
 endif
 
 ifneq ($(PY_INSTALL_DIR),)