Fix compile error on Linux and avoid slow test comile

Author: sidepelican

Sources/CallableKitMacros/CallableMacro.swift

@@ -1,3 +1,4 @@
+import Foundation
 import SwiftSyntax
 import SwiftSyntaxMacros
 

example/test.sh

@@ -2,15 +2,15 @@
 set -o pipefail
 
 swift package --allow-writing-to-package-directory codegen
-swift build -c release
+swift build
 
 APP=${1:-}
 case ${APP} in
   "vapor")
-    .build/release/VaporServer &
+    .build/debug/VaporServer &
     ;;
   "hummingbird")
-    .build/release/HBServer &
+    .build/debug/HBServer &
     ;;
   *)
     echo "$0 <vapor|hummingbird>"