gnu: xf86-input-keyboard: Remove Linux from supported systems.

* gnu/packages/xorg.scm (xf86-input-keyboard)[supported-systems]: New field.
(xpra)[inputs]: Remove xf86-input-keyboard.
* gnu/services/xorg.scm (%default-xorg-modules): Remove xf86-input-keyboard.
* doc/guix.texi (X Window)[%default-xorg-modules]: Replace xf86-input-keyboard
with xf86-input-libinput.

Change-Id: Ia0b5c0289aa83e3afa7e71bef1785d6bddf6f017

doc/guix.texi

@@ -24104,7 +24104,7 @@ SLiM@.  Thus, the configuration of these display managers aggregates an
 @table @asis
 @item @code{modules} (default: @code{%default-xorg-modules})
 This is a list of @dfn{module packages} loaded by the Xorg
-server---e.g., @code{xf86-video-vesa}, @code{xf86-input-keyboard}, and so on.
+server---e.g., @code{xf86-video-vesa}, @code{xf86-input-libinput}, and so on.
 
 @item @code{fonts} (default: @code{%default-xorg-fonts})
 This is a list of font directories to add to the server's @dfn{font path}.

gnu/packages/xorg.scm

@@ -2620,6 +2620,8 @@ It is used to control the pointer with a joystick device.")
           (base32
             "0mvwxrnkq0lzhjr894p420zxffdn34nc2scinmp7qd1hikr51kkp"))))
     (build-system gnu-build-system)
+    ;; Linux is no longer supported since 2.0.0, use libinput or evdev instead.
+    (supported-systems '("i586-gnu" "x86_64-gnu"))
     (inputs (list xorg-server))
     (native-inputs (list pkg-config))
     (home-page "https://www.x.org/wiki/")
@@ -6222,7 +6224,6 @@ basic eye-candy effects.")
            xorg-server
            xf86-video-dummy
            xf86-input-mouse
-           xf86-input-keyboard
            xxhash
            python-pillow
            ;; Optional dependencies.
@@ -6288,7 +6289,6 @@ basic eye-candy effects.")
                 "\nSection \"Files\"\nModulePath \""
                 #$(this-package-input "xf86-video-dummy") "/lib/xorg/modules,"
                 #$(this-package-input "xf86-input-mouse") "/lib/xorg/modules,"
-                #$(this-package-input "xf86-input-keyboard") "/lib/xorg/modules,"
                 #$(this-package-input "xorg-server") "/lib/xorg/modules\"\n"
                 "EndSection\n\n"))
               (substitute* '("xpra/scripts/config.py"

gnu/services/xorg.scm

@@ -165,9 +165,7 @@
         ;; Libinput is the new thing and is recommended over evdev/synaptics:
         ;; <http://who-t.blogspot.fr/2015/01/xf86-input-libinput-compatibility-with.html>.
         xf86-input-libinput
-
         xf86-input-evdev
-        xf86-input-keyboard
         xf86-input-mouse))
 
 (define %default-xorg-fonts