add toolchain-clean and default to FAKETIME off

Makefile

@@ -76,6 +76,11 @@ toolchain-update:
 		debian@sha256:$(DEBIAN_HASH) \
 		bash -c /usr/local/bin/packages-update
 
+.PHONY: toolchain-clean
+toolchain-clean:
+	rm -rf cache out
+	docker image rm -f local/$(NAME)-build
+
 .PHONY: attest
 attest:
 	rm -rf $(CACHE_DIR) $(OUT_DIR)

scripts/environment

@@ -17,7 +17,6 @@ cat <<- EOF
 	GIT_DATETIME=${GIT_DATETIME}
 	GIT_EPOCH=${GIT_EPOCH}
 	FAKETIME_FMT=%s
-	FAKETIME=1
 	SOURCE_DATE_EPOCH=1
 	KBUILD_BUILD_TIMESTAMP=1970-01-01 00:00:00 UTC
 	KCONFIG_NOTIMESTAMP=1