diff --git a/package/pkg-python.mk b/package/pkg-python.mk
index f031bc8fae..52ce402281 100644
--- a/package/pkg-python.mk
+++ b/package/pkg-python.mk
@@ -113,6 +113,8 @@ HOST_PKG_PYTHON_SETUPTOOLS_INSTALL_OPTS = \
 
 # Target pep517-based packages
 PKG_PYTHON_PEP517_ENV = \
+	_PYTHON_HOST_PLATFORM="$(PKG_PYTHON_HOST_PLATFORM)" \
+	_PYTHON_PROJECT_BASE="$(PYTHON3_DIR)" \
 	_PYTHON_SYSCONFIGDATA_NAME="$(PKG_PYTHON_SYSCONFIGDATA_NAME)" \
 	PATH=$(BR_PATH) \
 	$(TARGET_CONFIGURE_OPTS) \