Add jerbuild-binary make target

ober

0bc8f877c64ffd9c6f85f454615b827aa223ae27

diff --git a/Makefile b/Makefile
index f35d7a2..21b7f82 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ HOOK_DIR := $(TEMPLATE_DIR)/hooks
 
 .PHONY: run test binary install clean linux linux-local docker \
         verify-harden help install-native macos gitsafe-macos \
-        jerbuild-run jerbuild-test
+        jerbuild-run jerbuild-test jerbuild-binary
 
 .DEFAULT_GOAL := help
 
@@ -37,6 +37,16 @@ jerbuild-test:
 	  env -u JERBOA_HOME $(JERBUILD) exec \
 	    --libdirs $(CURDIR):$$JH/lib test/test-gitsafe.ss
 
+# Produce a standalone native gitsafe binary using only the jerbuild bundle
+# (no jerboa checkout, no Chez install). The resulting binary is self-contained.
+jerbuild-binary:
+	@JH=$$($(JERBUILD) --jerboa-home); \
+	  env -u JERBOA_HOME $(JERBUILD) binary \
+	    --libdirs $(CURDIR):$$JH/lib gitsafe/main.ss gitsafe-jerbuild
+	@echo ""
+	@ls -lh gitsafe-jerbuild
+	@file gitsafe-jerbuild
+
 install: $(if $(filter Darwin,$(shell uname -s)),gitsafe-macos,linux)
 	mkdir -p $(BIN_DIR)
 ifeq ($(shell uname -s),Darwin)
@@ -119,7 +129,7 @@ verify-harden: linux
 clean:
 	find . -name '*.so' -delete
 	find . -name '*.wpo' -delete
-	rm -f gitsafe-bin gitsafe-musl gitsafe-musl.sha256 gitsafe-macos gitsafe-macos.sha256
+	rm -f gitsafe-bin gitsafe-musl gitsafe-musl.sha256 gitsafe-macos gitsafe-macos.sha256 gitsafe-jerbuild
 
 # ── Help ─────────────────────────────────────────────────────────────────────
 help: