Makefile: codesign jerboa on macOS install; add jerbuild symlink

ober

57b62e928f413a432226908c1f02520c7202422b

diff --git a/Makefile b/Makefile
index 9c534f7..87b4549 100644
--- a/Makefile
+++ b/Makefile
@@ -255,9 +255,17 @@ install:
 	@test -x "$(CURDIR)/dist/jerboa" || { echo "ERROR: dist/jerboa not built — run 'make jerboa' first" >&2; exit 1; }
 	@mkdir -p "$(BINDIR)"
 	@install -m 0755 "$(CURDIR)/dist/jerboa" "$(BINDIR)/jerboa"
+	@# macOS: overwriting a Mach-O in place invalidates its (ad-hoc) code
+	@# signature, so the kernel SIGKILLs it ("Killed: 9"). Re-sign ad-hoc.
+	@case "$$(uname -s)" in Darwin) \
+		codesign --force --sign - "$(BINDIR)/jerboa" >/dev/null 2>&1 \
+		&& echo "Re-signed $(BINDIR)/jerboa (macOS Gatekeeper)" \
+		|| echo "WARNING: codesign failed — binary may be killed by Gatekeeper" >&2 ;; \
+	esac
 	@ln -sf jerboa "$(BINDIR)/jmcp"
 	@ln -sf jerboa "$(BINDIR)/jlsp"
-	@echo "Installed: $(BINDIR)/{jerboa,jmcp,jlsp}"
+	@ln -sf jerboa "$(BINDIR)/jerbuild"
+	@echo "Installed: $(BINDIR)/{jerboa,jmcp,jlsp,jerbuild}"
 	@case ":$$PATH:" in *":$(BINDIR):"*) ;; *) echo "NOTE: $(BINDIR) is not on PATH — add it to use these commands" >&2 ;; esac
 
 # ── Cross-compiled multicall binary ──────────────────────────────────────────