build-system/{gnu,cmake}: Remove #:patches and #:patch-flags parameters.

* guix/build/gnu-build-system.scm (patch): Remove.
  (%standard-phases): Remove 'patch'.
* guix/build-system/gnu.scm (gnu-build, gnu-cross-build): Remove
  #:patches and #:patch-flags parameters.
* guix/build-system/cmake.scm (cmake-build): Likewise.
* guix/build-system/python.scm (package-with-explicit-python): Update
  comment.

guix/build-system/cmake.scm

@@ -47,7 +47,6 @@
                      (outputs '("out")) (configure-flags ''())
                      (search-paths '())
                      (make-flags ''())
-                     (patches ''()) (patch-flags ''("--batch" "-p1"))
                      (cmake (default-cmake))
                      (out-of-source? #f)
                      (tests? #t)
@@ -81,8 +80,6 @@ provides a 'CMakeLists.txt' file as its build system."
                     #:search-paths ',(map search-path-specification->sexp
                                           (append search-paths
                                                   (standard-search-paths)))
-                    #:patches ,patches
-                    #:patch-flags ,patch-flags
                     #:phases ,phases
                     #:configure-flags ,configure-flags
                     #:make-flags ,make-flags

guix/build-system/gnu.scm

@@ -252,7 +252,6 @@ System: GCC, GNU Make, Bash, Coreutils, etc."
                     (search-paths '())
                     (configure-flags ''())
                     (make-flags ''())
-                    (patches ''()) (patch-flags ''("--batch" "-p1"))
                     (out-of-source? #f)
                     (tests? #t)
                     (test-target "check")
@@ -300,8 +299,6 @@ which could lead to gratuitous input divergence."
                   #:search-paths ',(map search-path-specification->sexp
                                         (append implicit-search-paths
                                                 search-paths))
-                  #:patches ,patches
-                  #:patch-flags ,patch-flags
                   #:phases ,phases
                   #:configure-flags ,configure-flags
                   #:make-flags ,make-flags
@@ -390,7 +387,6 @@ inputs."
 
                           (configure-flags ''())
                           (make-flags ''())
-                          (patches ''()) (patch-flags ''("--batch" "-p1"))
                           (out-of-source? #f)
                           (tests? #f)             ; nothing can be done
                           (test-target "check")
@@ -473,8 +469,6 @@ platform."
                                              search-path-specification->sexp
                                              (append implicit-host-search-paths
                                                      native-search-paths))
-                    #:patches ,patches
-                    #:patch-flags ,patch-flags
                     #:phases ,phases
                     #:configure-flags ,configure-flags
                     #:make-flags ,make-flags

guix/build-system/python.scm

@@ -58,9 +58,8 @@ prepended to the name."
   (let* ((build-system (package-build-system p))
          (rewrite-if-package
           (lambda (content)
-            ;; CONTENT may be a string (e.g., for patches), in which case it
-            ;; is returned, or a package, which is rewritten with the new
-            ;; PYTHON and NEW-PREFIX.
+            ;; CONTENT may be a file name, in which case it is returned, or a
+            ;; package, which is rewritten with the new PYTHON and NEW-PREFIX.
             (if (package? content)
                 (package-with-explicit-python content python
                                               old-prefix new-prefix)

guix/build/gnu-build-system.scm

@@ -115,14 +115,6 @@ makefiles."
   ;; Patch `SHELL' in generated makefiles.
   (for-each patch-makefile-SHELL (find-files "." "^(GNU)?[mM]akefile$")))
 
-(define* (patch #:key (patches '()) (patch-flags '("--batch" "-p1"))
-                #:allow-other-keys)
-  (every (lambda (p)
-           (format #t "applying patch `~a'~%" p)
-           (zero? (apply system* "patch"
-                         (append patch-flags (list "--input" p)))))
-         patches))
-
 (define* (configure #:key target native-inputs inputs outputs
                     (configure-flags '()) out-of-source?
                     #:allow-other-keys)
@@ -344,7 +336,7 @@ makefiles."
   ;; Standard build phases, as a list of symbol/procedure pairs.
   (let-syntax ((phases (syntax-rules ()
                          ((_ p ...) `((p . ,p) ...)))))
-    (phases set-paths unpack patch
+    (phases set-paths unpack
             patch-source-shebangs configure patch-generated-file-shebangs
             build check install
             patch-shebangs strip)))