build: configure 'c' plugin to use clang toolchain from dependencies

build.gradle

@@ -10,4 +10,20 @@ allprojects {
     if (path != ":dependencies") {
         evaluationDependsOn(":dependencies")
     }
+
+    afterEvaluate {
+        if (plugins.hasPlugin('c')) {
+            model {
+                toolChains {
+                    clang(Clang) {
+                        path "$llvmDir/bin"
+
+                        // The system PATH should be appended automatically according to Gradle docs,
+                        // but this doesn't seem to happen
+                        path System.env.PATH.split(File.pathSeparator)
+                    }
+                }
+            }
+        }
+    }
 }