README.md: Updated build instructions

README.md

@@ -24,32 +24,41 @@ PRs welcome! Shock me with your radical ideas! :-)
 
 ### Compilation
 
-RaptorJIT is built using GNU Make, Clang (C compiler), and LuaJIT 2 (bootstrap Lua for DynASM etc.) The build environment is specified formally in `default.nix` and can be automatically provided using the [nix](http://nixos.org/nix/) package manager.
+RaptorJIT uses [nix](http://nixos.org/nix/) to define a reproducible
+build environment that includes Clang for C and LuaJIT 2.0 for
+bootstrapping. The recommended way to build RaptorJIT is with nix,
+which provides the dependencies automatically, but you can build
+manually if you prefer.
 
-Here is how to install nix:
+#### Build with nix
+
+Install nix:
 
 ```
 $ curl https://nixos.org/nix/install | sh
 ```
 
-Here is how to build raptorjit once nix is installed (note: the first
-compilation takes time to download dependencies):
+Build in batch-mode (option 1):
 
 ```shell
 $ nix-build    # produces result/bin/raptorjit
 ```
 
-Here is the interactive version:
+Build interactively (option 2):
 
-```
+```shell
 $ nix-shell    # start sub-shell with pristine build environment in $PATH
 [nix-shell]$ make -j    # build manually as many times as you like
 [nix-shell]$ exit       # quit when done
 ```
 
-(You can also skip `nix` and install `clang` and `luajit` yourself if
-you like. The nix approach is future proof to new dependencies and
-allows for pinning specific versions.)
+#### Build without nix
+
+```shell
+$ make
+```
+
+... but make sure you have at least `make`, `clang`, and `luajit` in your `$PATH`.
 
 ### Quotes