backend/drm: add hardcoded hwdata path fallback

Add hardcoded fallback "/usr/share/hwdata/pnp.ids" as a
temporary solution to get things working in Guix until
hwdata ships with pkg-config file.

diff --git a/backend/drm/meson.build b/backend/drm/meson.build
index 6fcb2c15..ed95360a 100644
--- a/backend/drm/meson.build
+++ b/backend/drm/meson.build
@@ -1,8 +1,7 @@
 hwdata = dependency(
 	'hwdata',
-	required: 'drm' in backends,
+	required: false,
 	native: true,
-	not_found_message: 'Required for the DRM backend.',
 )
 
 libdisplay_info = dependency(
@@ -19,15 +18,21 @@ libliftoff = dependency(
 	required: false,
 )
 
-if not (hwdata.found() and libdisplay_info.found() and features['session'])
+if hwdata.found()
+	hwdata_dir = hwdata.get_variable(pkgconfig: 'pkgdatadir')
+	pnp_ids = files(hwdata_dir / 'pnp.ids')
+else
+	pnp_ids = files('/usr/share/hwdata/pnp.ids')
+endif
+
+if not (libdisplay_info.found() and features['session'])
 	subdir_done()
 endif
 
-hwdata_dir = hwdata.get_variable(pkgconfig: 'pkgdatadir')
 pnpids_c = custom_target(
 	'pnpids.c',
 	output: 'pnpids.c',
-	input: files(hwdata_dir / 'pnp.ids'),
+	input: pnp_ids,
 	feed: true,
 	capture: true,
 	command: files('gen_pnpids.sh'),

/guix/tree/tests/records.scm?id=2f7e80102defc6c4e469d1dc94441e7f054e5310'>tree</a><a href='/guix/commit/tests/records.scm?id=2f7e80102defc6c4e469d1dc94441e7f054e5310'>commit</a><a href='/guix/diff/tests/records.scm?id=2f7e80102defc6c4e469d1dc94441e7f054e5310'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/tests/records.scm'>
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<div class='path'>path: <a href='/guix/log/?id=2f7e80102defc6c4e469d1dc94441e7f054e5310'>root</a>/<a href='/guix/log/tests?id=2f7e80102defc6c4e469d1dc94441e7f054e5310'>tests</a>/<a href='/guix/log/tests/records.scm?id=2f7e80102defc6c4e469d1dc94441e7f054e5310'>records.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/tests/records.scm?id=2f7e80102defc6c4e469d1dc94441e7f054e5310&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-06-04 10:59:28 +0200'>2023-06-04</span></td><td><a href='/guix/commit/tests/records.scm?id=178ffed3b7fe1784fff67b963c5c4bb667fbad2a'>tests: records: Add test for ellipsis in body.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/records.scm ("match-record, ellipsis in body"): New test.
</span></span></td><td>Josselin Poiret</td></tr>
<tr><td><span title='2023-06-04 10:59:25 +0200'>2023-06-04</span></td><td><a href='/guix/commit/tests/records.scm?id=4cd529362108086eeec25d4d465261415cff45b3'>records: Add MATCH-RECORD-LAMBDA.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/records.scm (match-record-lambda): New syntax.
* tests/records.scm ("match-record-lambda"): New test.

Signed-off-by: Josselin Poiret &lt;dev@jpoiret.xyz&gt;
</span></span></td><td>(unmatched-parenthesis ew syntax</td></tr>
<tr><td><span title='2023-06-04 10:34:35 +0200'>2023-06-04</span></td><td><a href='/guix/commit/tests/records.scm?id=b88e38d4b51b9aa0e857baeb614c000e491ad309'>records: match-record: Support thunked and delayed fields.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/records.scm (match-record): Unwrap matched thunked and delayed fields.
* tests/records.scm ("match-record, thunked field",
"match-record, delayed field"): New tests.

Signed-off-by: Josselin Poiret &lt;dev@jpoiret.xyz&gt;
</span></span></td><td>(unmatched-parenthesis d</td></tr>
<tr><td><span title='2022-12-27 23:53:42 +0100'>2022-12-27</span></td><td><a href='/guix/commit/tests/records.scm?id=363b20b68584d71556c2d8912dd07cbdacabdb25'>records: match-record supports specifying a different variable name.</a><span class='msg-avail'>...<span class='msg-tooltip'>An example:

(match-record obj &lt;my-type&gt;
  (field1 (field2 custom-var-name) field3)
  ...)

* guix/records.scm (match-record-inner): Add support for the new syntax.
* tests/records.scm ("match-record, simple"): Add a simple test case for the
new syntax.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Attila Lendvai</td></tr>
<tr><td><span title='2022-12-02 00:02:12 +0100'>2022-12-02</span></td><td><a href='/guix/commit/tests/records.scm?id=7c1161dba4c8930d3a500a72ccaaaf50df73f466'>records: 'match-record' checks fields at macro-expansion time.</a><span class='msg-avail'>...<span class='msg-tooltip'>This allows 'match-record' to be more efficient (field offsets are
computed at compilation time) and to report unknown fields at
macro-expansion time.

* guix/records.scm (map-fields): New macro.
(define-record-type*)[rtd-identifier]: New procedure.
Define TYPE as a macro and use a separate identifier for the RTD.
(lookup-field, match-record-inner): New macros.
(match-record): Rewrite in terms of 'match-error-inner'.
* tests/records.scm ("match-record, simple")
("match-record, unknown field"): New tests.
* gnu/services/cuirass.scm (cuirass-shepherd-service): Rename 'log-file'
local variable to 'main-log-file'.
* gnu/services/getmail.scm (serialize-getmail-configuration-file): Move
after &lt;getmail-configuration-file&gt; definition.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-07-01 12:10:29 +0200'>2022-07-01</span></td><td><a href='/guix/commit/tests/records.scm?id=741895676b124a8a9a6656a54b5b58fd35d8e0f9'>tests: Add sanitizer test.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/records.scm ("define-record-type* &amp; sanitize without default
value"): New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-08-12 12:34:13 +0200'>2021-08-12</span></td><td><a href='/guix/commit/tests/records.scm?id=5291fd7a4205394b863a8705b32fbb447321dc60'>records: Support field sanitizers.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/records.scm (make-syntactic-constructor): Add #:sanitizers.
[field-sanitizer]: New procedure.
[wrap-field-value]: Honor F's sanitizer.
(define-record-type*)[field-sanitizer]: New procedure.
Pass #:sanitizer to 'make-syntactic-constructor'.
* tests/records.scm ("define-record-type* &amp; sanitize")
("define-record-type* &amp; sanitize &amp; thunked"): New tests.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-04-29 01:22:04 +0200'>2021-04-29</span></td><td><a href='/guix/commit/tests/records.scm?id=524c9800afb433cc474132185d8e37f72004adb3'>diagnostics, ui: Adjust to 'read-error' and 'syntax-error' in Guile 3.0.6.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/diagnostics.scm (source-properties-&gt;location): Add clause for
vectors.
* guix/ui.scm (report-load-error): Tweak 'read-error' handling for 3.0.6.
* tests/guix-package.sh: Relax regexp for the "unbound variable"
diagnostic check.
* tests/guix-system.sh: Adjust "missing closing paren" check for 3.0.6.
* tests/records.scm (location-alist): New procedure.
("define-record-type* &amp; wrong field specifier")
("define-record-type* &amp; wrong field specifier, identifier")
("define-record-type* &amp; duplicate initializers"): Use it.
</span></span></td><td>Ludovic Courtès</td></tr>