gnu: emacs: Fix indentation of scheme keyword lists.

* gnu/packages/patches/emacs-fix-scheme-indent-function.patch: New patch.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/emacs.scm (emacs)[source]: Use it.

gnu/local.mk

@@ -472,6 +472,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/elfutils-tests-ptrace.patch		\
   %D%/packages/patches/einstein-build.patch			\
   %D%/packages/patches/emacs-exec-path.patch			\
+  %D%/packages/patches/emacs-fix-scheme-indent-function.patch	\
   %D%/packages/patches/emacs-scheme-complete-scheme-r5rs-info.patch	\
   %D%/packages/patches/emacs-source-date-epoch.patch		\
   %D%/packages/patches/eudev-rules-directory.patch		\

gnu/packages/emacs.scm

@@ -80,6 +80,7 @@ (define-public emacs
               (base32
                "0kn3rzm91qiswi0cql89kbv6mqn27rwsyjfb8xmwy9m5s8fxfiyx"))
              (patches (search-patches "emacs-exec-path.patch"
+                                      "emacs-fix-scheme-indent-function.patch"
                                       "emacs-source-date-epoch.patch"))
              (modules '((guix build utils)))
              (snippet

gnu/packages/patches/emacs-fix-scheme-indent-function.patch

@@ -0,0 +1,29 @@
+Fix 'scheme-indent-function' to indent s-expressions starting with a keyword
+properly, like this:
+
+(#:foo 1
+ #:bar 2)
+
+instead of like this:
+
+(#:foo 1
+       #:bar 2)
+
+The fix is made by Mark H Weaver <mhw@netris.org>:
+<http://www.netris.org/~mhw/scheme-indent-function.el>
+
+--- a/lisp/progmodes/scheme.el
++++ b/lisp/progmodes/scheme.el
+@@ -482,6 +482,12 @@
+ 			(> (length function) 3)
+ 			(string-match "\\`def" function)))
+ 	       (lisp-indent-defform state indent-point))
++              ((and (null method)
++                    (> (length function) 1)
++                    ;; The '#' in '#:' seems to get lost, not sure why
++                    (string-match "\\`:" function))
++               (let ((lisp-body-indent 1))
++                 (lisp-indent-defform state indent-point)))
+ 	      ((integerp method)
+ 	       (lisp-indent-specform method state
+ 				     indent-point normal-indent))