Fix conflicts with ading function_exists in Support functions

src/Illuminate/Support/functions.php

@@ -6,32 +6,36 @@
 use Illuminate\Support\Defer\DeferredCallbackCollection;
 use Illuminate\Support\Process\PhpExecutableFinder;
 
-/**
- * Defer execution of the given callback.
- *
- * @param  callable|null  $callback
- * @param  string|null  $name
- * @param  bool  $always
- * @return \Illuminate\Support\Defer\DeferredCallback
- */
-function defer(?callable $callback = null, ?string $name = null, bool $always = false)
-{
-    if ($callback === null) {
-        return app(DeferredCallbackCollection::class);
-    }
+if (! function_exists('defer')) {
+    /**
+     * Defer execution of the given callback.
+     *
+     * @param  callable|null  $callback
+     * @param  string|null  $name
+     * @param  bool  $always
+     * @return \Illuminate\Support\Defer\DeferredCallback
+     */
+    function defer(?callable $callback = null, ?string $name = null, bool $always = false)
+    {
+        if ($callback === null) {
+            return app(DeferredCallbackCollection::class);
+        }
 
-    return tap(
-        new DeferredCallback($callback, $name, $always),
-        fn ($deferred) => app(DeferredCallbackCollection::class)[] = $deferred
-    );
+        return tap(
+            new DeferredCallback($callback, $name, $always),
+            fn ($deferred) => app(DeferredCallbackCollection::class)[] = $deferred
+        );
+    }
 }
 
-/**
- * Determine the PHP Binary.
- *
- * @return string
- */
-function php_binary()
-{
-    return (new PhpExecutableFinder)->find(false) ?: 'php';
+if (! function_exists('defer')) {
+    /**
+     * Determine the PHP Binary.
+     *
+     * @return string
+     */
+    function php_binary()
+    {
+        return (new PhpExecutableFinder)->find(false) ?: 'php';
+    }
 }