gnu: gcc-11: Fix patch-hurd-libpthread phase.

It didn't work when it was introduced in
08acdd0765.

* gnu/packages/gcc.scm (gcc-11)[arguments]: Remove the procedure arguments,
and use %build-inputs rather than inputs.
* gnu/packages/commencement.scm (gcc-boot0)[native-inputs]: Add hurd-patch, as
this package inherits from gcc-11.

gnu/packages/commencement.scm

@@ -2452,7 +2452,10 @@ (define gcc-boot0
               ,@(alist-delete "libc" (%boot0-inputs))))
 
     ;; No need for the native-inputs to build the documentation at this stage.
-    (native-inputs `())))
+    (native-inputs
+     (if (target-hurd?)
+         `(("hurd-patch" ,(search-patch "gcc-11-libstdc++-hurd-libpthread.patch")))
+         '()))))
 
 (define perl-boot0
   (package

gnu/packages/gcc.scm

@@ -719,10 +719,9 @@ (define-public gcc-11
        (if (target-hurd?)
            `(modify-phases ,phases
               (add-after 'unpack 'patch-hurd-libpthread
-                (lambda (#:key inputs)
+                (lambda _
                   (invoke "patch" "--force" "-p1" "-i"
-                          (assoc-ref inputs "hurd-patch")
-                          patch))))
+                          (assoc-ref %build-inputs "hurd-patch")))))
            phases))))
    (properties
     `((compiler-cpu-architectures