Reorganize language bindings

* Move rust binding: lib/binding -> lib/binding_rust
* Move wasm bindinig: lib/web -> lib/binding_web
* Add wasm readme

lib/binding_rust/build.rs

@@ -0,0 +1,58 @@
+extern crate cc;
+
+use std::{env, fs};
+use std::path::{Path, PathBuf};
+
+fn main() {
+    println!("cargo:rerun-if-env-changed=TREE_SITTER_STATIC_ANALYSIS");
+    if env::var("TREE_SITTER_STATIC_ANALYSIS").is_ok() {
+        if let (Some(clang_path), Some(scan_build_path)) = (which("clang"), which("scan-build")) {
+            let clang_path = clang_path.to_str().unwrap();
+            let scan_build_path = scan_build_path.to_str().unwrap();
+            env::set_var(
+                "CC",
+                &format!(
+                    "{} -analyze-headers --use-analyzer={} cc",
+                    scan_build_path, clang_path
+                ),
+            );
+        }
+    }
+
+    let mut config = cc::Build::new();
+
+    println!("cargo:rerun-if-env-changed=TREE_SITTER_TEST");
+    if env::var("TREE_SITTER_TEST").is_ok() {
+        config.define("TREE_SITTER_TEST", "");
+    }
+
+    let src_path = Path::new("src");
+
+    for entry in fs::read_dir(&src_path).unwrap() {
+        let entry = entry.unwrap();
+        let path = src_path.join(entry.file_name());
+        println!("cargo:rerun-if-changed={}", path.to_str().unwrap());
+    }
+
+    config
+        .flag_if_supported("-std=c99")
+        .flag_if_supported("-Wno-unused-parameter")
+        .include("include")
+        .include("utf8proc")
+        .file(src_path.join("lib.c"))
+        .file(Path::new("binding_rust").join("helper.c"))
+        .compile("tree-sitter");
+}
+
+fn which(exe_name: impl AsRef<Path>) -> Option<PathBuf> {
+    env::var_os("PATH").and_then(|paths| {
+        env::split_paths(&paths).find_map(|dir| {
+            let full_path = dir.join(&exe_name);
+            if full_path.is_file() {
+                Some(full_path)
+            } else {
+                None
+            }
+        })
+    })
+}