add shared library documentation (#43)

* add docs for loading ckb-lua dynamic library

* add pointer to the dylib tutorial, make dylib example runnable

Makefile

@@ -15,7 +15,7 @@ DOCKER_EXTRA_FLAGS ?=
 BUILDER_DOCKER := nervos/ckb-riscv-gnu-toolchain@sha256:aae8a3f79705f67d505d1f1d5ddc694a4fd537ed1c7e9622420a470d59ba2ec3
 PORT ?= 9999
 
-all: lualib/liblua.a build/lua-loader build/libckblua.so build/dylibtest
+all: lualib/liblua.a build/lua-loader build/libckblua.so build/dylibtest build/dylibexample
 
 all-via-docker:
 	docker run --rm -v `pwd`:/code ${BUILDER_DOCKER} bash -c "cd /code && make"
@@ -29,6 +29,9 @@ lualib/liblua.a:
 build/dylibtest: tests/test_cases/dylibtest.c
 	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $< $(shell $(CC) --print-search-dirs | sed -n '/install:/p' | sed 's/install:\s*//g')libgcc.a
 
+build/dylibexample: examples/dylib.c
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $< $(shell $(CC) --print-search-dirs | sed -n '/install:/p' | sed 's/install:\s*//g')libgcc.a
+
 build/lua-loader.o: lua-loader/lua-loader.c
 	$(CC) -c $(CFLAGS) -o $@ $<
 

README.md

@@ -14,7 +14,7 @@ make all-via-docker
 There are 2 ways to use this project:
 1. Embedded
 
-Use `build/libckblua.so` as a shared library. TODO
+Use `build/libckblua.so` as a shared library. See [dylib.md](./docs/dylib.md) for a detailed tutorial on how to use `build/libckblua.so`.
 
 2. Standalone(used as script)