Add support for version

Author: Clement Cheung

devcontainer-feature.json

@@ -4,7 +4,19 @@
   "name": "llvm",
   "documentationURL": "https://github.com/devcontainers-community/features-llvm",
   "description": "Installs llvm on debian based systems",
-  "options": {},
+  "options": {
+    "version": {
+      "type": "string",
+      "proposals": [
+        "latest",
+        "18",
+        "17",
+        "16"
+      ],
+      "default": "latest",
+      "description": "LLVM version"
+    }
+  },
   "mounts": [],
   "installsAfter": [
       "ghcr.io/devcontainers/features/common-utils"

install.sh

@@ -1,10 +1,28 @@
 #!/usr/bin/env bash
 set -e
 
-apt update && apt install lsb-release wget software-properties-common gnupg -y -qq
+if [ "$VERSION" == "latest" ]; then
+  VERSION=
+fi
+MAJOR_VERSION=${VERSION%%.*}
 
-bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
+# Checks if packages are installed and installs them if not
+check_packages() {
+    if ! dpkg -s "$@" > /dev/null 2>&1; then
+        apt_get_update
+        apt-get -y install --no-install-recommends "$@"
+    fi
+}
 
-ln -s /usr/bin/clang-17 /usr/bin/clang
-ln -s /usr/bin/clang++-17 /usr/bin/clang++
-ln -s /usr/bin/lld-17 /usr/bin/lld
+check_packages lsb-release wget software-properties-common gnupg
+
+cd /tmp
+wget https://apt.llvm.org/llvm.sh
+chmod +x llvm.sh
+./llvm.sh $VERSION
+rm llvm.sh
+
+ln -sf /usr/bin/clang-${MAJOR_VERSION} /usr/bin/clang
+ln -sf /usr/bin/clang++-${MAJOR_VERSION} /usr/bin/clang++
+ln -sf /usr/bin/lld-${MAJOR_VERSION} /usr/bin/lld
+ln -sf /usr/bin/ld.lld-${MAJOR_VERSION} /usr/bin/ld.lld