Makefile: list cross-platform jerboa targets in `make help`

ober

d869482ed07a610232425fccddd5e2657a08ed93

diff --git a/Makefile b/Makefile
index 1e06315..ec5290c 100644
--- a/Makefile
+++ b/Makefile
@@ -74,6 +74,16 @@ help:
 	@echo "  audit-native     Run cargo audit on Rust native library"
 	@echo "  pure-audit       Scan jerboa-* repos for non-pure runtime surfaces"
 	@echo ""
+	@echo "Cross-platform binaries (one static jerboa + jerbuild/jmcp/jlsp symlinks):"
+	@echo "  jerboa-linux-amd64    Cross-build for Linux x86_64 (musl)   -> dist/linux-amd64/"
+	@echo "  jerboa-freebsd-amd64  Cross-build for FreeBSD amd64          -> dist/freebsd-amd64/"
+	@echo "  jerboa-cross          Generic: CHEZ_TARGET_MACHINE=<mt> CROSS_CC=<cc>"
+	@echo "                        (e.g. tarm64le -> dist/linux-arm64/, ta6fb -> freebsd-amd64)"
+	@echo "  jerbuild-cross        Cross-build standalone jerbuild-<mt>  (same args)"
+	@echo "  jerboa-portable       Host + linux-amd64 + freebsd-amd64 in one shot"
+	@echo "  NOTE one-time per target: build the cross Chez first, e.g."
+	@echo "    make chez-cross CHEZ_TARGET_MACHINE=ta6le CROSS_CC=x86_64-linux-musl-gcc   # Linux amd64"
+	@echo ""
 	@echo "MCP server (jerboa-mcp + jmcp binary):"
 	@echo "  mcp              Compile-check the MCP server (mcp/server.ss)"
 	@echo "  mcp-run          Run the MCP server from source over stdio"