Copied from Debian.

From 03a820b173ed1fdef6ff14b4468f5dbc02ff59be Mon Sep 17 00:00:00 2001
From: Heiko Lewin <heiko.lewin@worldiety.de>
Date: Tue, 15 Dec 2020 16:48:19 +0100
Subject: [PATCH] Fix mask usage in image-compositor

[trimmed test case, since not used in Debian build]

---
 src/cairo-image-compositor.c                |   8 ++--

--- cairo-1.16.0.orig/src/cairo-image-compositor.c
+++ cairo-1.16.0/src/cairo-image-compositor.c
@@ -2601,14 +2601,14 @@ _inplace_src_spans (void *abstract_rende
 		    unsigned num_spans)
 {
     cairo_image_span_renderer_t *r = abstract_renderer;
-    uint8_t *m;
+    uint8_t *m, *base = (uint8_t*)pixman_image_get_data(r->mask);
     int x0;
 
     if (num_spans == 0)
 	return CAIRO_STATUS_SUCCESS;
 
     x0 = spans[0].x;
-    m = r->_buf;
+    m = base;
     do {
 	int len = spans[1].x - spans[0].x;
 	if (len >= r->u.composite.run_length && spans[0].coverage == 0xff) {
@@ -2646,7 +2646,7 @@ _inplace_src_spans (void *abstract_rende
 				      spans[0].x, y,
 				      spans[1].x - spans[0].x, h);
 
-	    m = r->_buf;
+	    m = base;
 	    x0 = spans[1].x;
 	} else if (spans[0].coverage == 0x0) {
 	    if (spans[0].x != x0) {
@@ -2675,7 +2675,7 @@ _inplace_src_spans (void *abstract_rende
 #endif
 	    }
 
-	    m = r->_buf;
+	    m = base;
 	    x0 = spans[1].x;
 	} else {
 	    *m++ = spans[0].coverage;
uix/commit/gnu/system/mapped-devices.scm?id=3339f6f5503d86b418753533afdca2dddb253e2f'>commit</a><a href='/guix/diff/gnu/system/mapped-devices.scm?id=3339f6f5503d86b418753533afdca2dddb253e2f'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/system/mapped-devices.scm'>
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<div class='path'>path: <a href='/guix/log/?id=3339f6f5503d86b418753533afdca2dddb253e2f'>root</a>/<a href='/guix/log/gnu?id=3339f6f5503d86b418753533afdca2dddb253e2f'>gnu</a>/<a href='/guix/log/gnu/system?id=3339f6f5503d86b418753533afdca2dddb253e2f'>system</a>/<a href='/guix/log/gnu/system/mapped-devices.scm?id=3339f6f5503d86b418753533afdca2dddb253e2f'>mapped-devices.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/system/mapped-devices.scm?id=3339f6f5503d86b418753533afdca2dddb253e2f&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-04-08 18:14:35 +0200'>2022-04-08</span></td><td><a href='/guix/commit/gnu/system/mapped-devices.scm?id=931f13840bad7bd3cb98b7806f09ca2b3cf7cd10'>mapped-devices: Ensure 'cryptsetup open' gets a tty.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://issues.guix.gnu.org/54770&gt;.
Regression introduced in 400c9ed3d779308e56038305d40cd93acb496180.

Previously, for an encrypted /home (say), "cryptsetup open" would be
invoked by shepherd, with /dev/null as its standard input.  It would
thus run in non-interactive mode and, instead of asking for a
passphrase, fail with:

  Nothing to read on input.

This change ensures it runs in interactive mode.

* gnu/build/file-systems.scm (system*/console, system*/tty): New
procedures.
* gnu/system/mapped-devices.scm (open-luks-device): Use 'system*/tty'
instead of 'system*'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-12-01 17:51:37 +0100'>2021-12-01</span></td><td><a href='/guix/commit/gnu/system/mapped-devices.scm?id=adce91a3ec0cb2912daa6eefe9324c15ff3126f7'>gnu: system: Add LUKS2 support for the root file system.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/bootloader/grub.scm (grub-configuration-file): Add 'insmod
luks2'.
* gnu/system/mapped-devices.scm (open-luks-device): Create
'/run/cryptsetup/' directory.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Josselin Poiret</td></tr>
<tr><td><span title='2021-01-13 22:24:18 +0100'>2021-01-13</span></td><td><a href='/guix/commit/gnu/system/mapped-devices.scm?id=0d22fc8d36e4efba9748c94cab7cedbbe2bbb5bf'>services: shepherd: 'shepherd-service-type' requires documentation.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/shepherd.scm (shepherd-service-type): Require a
'description' form.
* gnu/services/base.scm (root-file-system-service-type)
(rngd-service-type, host-name-service-type):
(virtual-terminal-service-type, console-keymap-service-type)
(syslog-service-type, swap-service-type)
(kmscon-service-type): Add description.
* gnu/services/networking.scm (dhcp-client-service-type): Likewise.
* gnu/system/install.scm (cow-store-service-type): Likewise.
* gnu/system/linux-container.scm (dummy-networking-service-type):
Likewise.
* gnu/system/mapped-devices.scm (device-mapping-service-type):
Likewise.
* tests/guix-system.sh: Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>