Update DEV.md

DEV.md

@@ -1,11 +1,23 @@
 # M3/Wasm development notes
 
+M3/Wasm project uses CMake. It can also be easily integarted into any build system.
+General build steps look like:
+```sh
+mkdir -p build
+cd build
+cmake ..
+make -j8
+```
+
+It's recommended to use Clang/Ninja to build the project
 
 ## Build on Linux
 
 ### Clang (recommended)
 
 ```sh
+mkdir -p build
+cd build
 cmake -GNinja -DCLANG_SUFFIX="-9" ..
 ninja
 ```
@@ -21,13 +33,15 @@ ninja
 
 You may need to install:
 - [Build Tools for Visual Studio 2019](https://visualstudio.microsoft.com/downloads/#build-tools-for-visual-studio-2019)
+- [CMake](https://cmake.org/download/)
 - [Ninja](https://github.com/ninja-build/ninja/releases)
 - [Clang 9](https://releases.llvm.org/download.html#9.0.0)
 
-
 ### Clang with Ninja (recommended)
 
 ```bat
+mkdir build
+cd build
 cmake -GNinja -DCLANG_CL=1 ..
 ninja
 ```
@@ -52,3 +66,14 @@ MSBuild /p:Configuration=Release wasm3.sln
 cmake -GNinja ..
 ninja
 ```
+
+## Running WebAssembly spec tests
+
+To run spec tests, you need `python3` and `WABT` (The WebAssembly Binary Toolkit).
+
+```sh
+cd test
+python3 ./run-spec-test.py
+```
+
+It will automatically download, extract, preprocess the WebAssembly core test suite.