diff --git a/eden/scm/.gitignore b/eden/scm/.gitignore
index 6b560ef4fb..efda8abfbb 100644
--- a/eden/scm/.gitignore
+++ b/eden/scm/.gitignore
@@ -87,9 +87,10 @@ wheelhouse/
 hg-python
 hg.py
 
-# mercurial binary
+# scm binary
 hg
 hg3
+sl
 
 # make-local Windows artifacts
 hgrc.d
diff --git a/eden/scm/Makefile b/eden/scm/Makefile
index 101798c1cc..1edeb5874b 100644
--- a/eden/scm/Makefile
+++ b/eden/scm/Makefile
@@ -67,8 +67,8 @@ help:
 all: build
 
 oss:
-	export HGNAME=sl
-	SAPLING_OSS_BUILD=true \
+	$(eval HGNAME = sl)
+	SAPLING_OSS_BUILD=true HGNAME=$(HGNAME) \
 	  $(shell $(PYTHON3) contrib/pick_python.py $(PYTHON3)) setup_with_version.py $(PURE) \
 	  build_interactive_smartlog \
 	  build_py -c -d . \