Add install_tools target to build.sh and fix LLVM CI.

.github/workflows/llvm.yml

@@ -45,6 +45,10 @@ jobs:
         shell: powershell
         run: build/intrin.ps1
 
+      - name: Install dependencies
+        shell: bash
+        run: build/build.sh install_tools
+
       - name: Clone LLVM
         shell: bash
         run: build/premake.sh --file=build/scripts/LLVM.lua clone_llvm

build/build.sh

@@ -181,6 +181,9 @@ case "$cmd" in
   download_llvm)
     download_llvm
     ;;
+  install_tools)
+    download_premake
+    ;;
    *)
     build
     ;;