Install the C SDK correctly

.github/workflows/main.yml

@@ -100,5 +100,8 @@ jobs:
         ./install-solana.sh
         echo "$HOME/.local/share/solana/install/active_release/bin" >> $GITHUB_PATH
 
+    - name: Install C compiler
+      run: ./install-solana-c.sh
+
     - name: Build and test program
       run: ./test-c.sh ${{ matrix.program }}

helloworld/c/Makefile

@@ -1,4 +1,4 @@
-LOCAL_PATH := /home/$(USER)/.local/share/solana/install/active_release/bin/sdk/sbf/c/
+LOCAL_PATH := ../../solana-c-sdk/c/
 
 .PHONY: all clean
 

install-solana-c.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+
+if [[ -n $SOLANA_VERSION ]]; then
+  solana_version="$SOLANA_VERSION"
+else
+  solana_version="v2.0.8"
+fi
+
+output_dir="$1"
+if [[ -z $output_dir ]]; then
+  output_dir="solana-c-sdk"
+fi
+output_dir="$(mkdir -p "$output_dir"; cd "$output_dir"; pwd)"
+cd $output_dir
+
+sdk_tar="sbf-sdk.tar.bz2"
+sdk_release_url="https://github.com/anza-xyz/agave/releases/download/$solana_version/$sdk_tar"
+echo "Downloading $sdk_release_url"
+curl --proto '=https' --tlsv1.2 -SfOL "$sdk_release_url"
+echo "Unpacking $sdk_tar"
+tar -xjf $sdk_tar
+rm $sdk_tar
+
+# Install platform-tools
+mv sbf-sdk/* .
+rmdir sbf-sdk
+./scripts/install.sh
+echo "solana-c compiler available at $output_dir"