Speed up llvm clone by specifying depth and branch name

Co-Authored-By: Daniel Henry-Mantilla <[email protected]>

Author: hamchapman

build.sh

@@ -22,7 +22,7 @@ mkdir -p "$WORKING_DIR"
 
 cd "$WORKING_DIR"
 if [ ! -d "$WORKING_DIR/llvm-project" ]; then
-    git clone https://github.com/apple/llvm-project.git
+    git clone --depth 1 --branch "$LLVM_BRANCH" https://github.com/apple/llvm-project.git
 fi
 cd "$WORKING_DIR/llvm-project"
 git reset --hard

config.sh

@@ -3,7 +3,7 @@
 # returned by the command below:
 # $ xcrun -sdk iphoneos swiftc --version
 
-LLVM_BRANCH="tags/swift-5.3.2-RELEASE"
+LLVM_BRANCH="swift-5.3.2-RELEASE"
 
 # 2. Select the best branch, tag or commit hash from https://github.com/rust-lang/rust