Distriction specific patch, not going upstream

Disable systemd-run if the command is not found.

diff --git a/xpra/scripts/main.py b/xpra/scripts/main.py
index 3813331a5..46e2c83a6 100755
--- a/xpra/scripts/main.py
+++ b/xpra/scripts/main.py
@@ -337,23 +337,26 @@ def use_systemd_run(s) -> bool:
     cmd = ["systemd-run", "--quiet"]
     if getuid()!=0:
         cmd += ["--user"]
-    cmd += ["--scope", "--", "true"]
-    proc = Popen(cmd, stdout=PIPE, stderr=PIPE, shell=False)
     try:
-        proc.communicate(timeout=2)
-        r = proc.returncode
-    except TimeoutExpired:  # pragma: no cover
-        r = None
-    if r is None:
-        try:
-            proc.terminate()
-        except Exception:
-            pass
+        cmd = ["systemd-run", "--quiet", "--user", "--scope", "--", "true"]
+        proc = Popen(cmd, stdout=PIPE, stderr=PIPE, shell=False)
         try:
-            proc.communicate(timeout=1)
+            proc.communicate(timeout=2)
+            r = proc.returncode
         except TimeoutExpired:  # pragma: no cover
             r = None
-    return r==0
+        if r is None:
+            try:
+                proc.terminate()
+            except Exception:
+                pass
+            try:
+                proc.communicate(timeout=1)
+            except TimeoutExpired:  # pragma: no cover
+                r = None
+        return r==0
+    except FileNotFoundError:
+        return False
 
 def verify_gir():
     try:
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<tr><td><span title='2023-07-11 12:21:00 -0400'>2023-07-11</span></td><td><a href='/guix/commit/gnu/packages/patches/rocm-opencl-runtime-4.3-noclinfo.patch?id=15f9870eb36e688fac2af37828971779b6c56916'>gnu: rocm: Update to 5.6.0.</a><span class='msg-avail'>...<span class='msg-tooltip'>Update all of the ROCm packages at the same time as they share a version
number and should be upgraded together, including llvm-for-rocm.

* gnu/packages/llvm.scm (llvm-for-rocm): Update to 5.6.0.
[source]{patches}: Remove unneeded patches (linkdl and remove-isystem-usr-include).
* gnu/packages/rocm.scm (rocm-cmake, roct-thunk-interface): Update
to 5.6.0.
(rocclr-src): Update to 5.6.0.
[source]{patches}: Add enable-gfx800 patch.
(rocm-device-libs):  Update to 5.6.0.
[inputs]: Update style.
(rocm-comgr): Update to 5.6.0.
[inputs]: Remove lld.  Update style.
(rocr-runtime): Update to 5.6.0.
[arguments]: Use gexps.  Remove configure-flags.  Add add-rocm-device-lib-path
phase.
[inputs]: Add libdrm.  Update style.
[native-inputs]: Add pkg-config.  Update style.
(rocm-opencl-runtime): Update to 5.6.0.
[source]{patches}: Remove noopencl patch.
[arguments]{configure-flags}: Add BUILD_ICD=OFF and
FILE_REORG_BACKWARD_COMPATIBILITY=OFF flags.
[inputs]: Add opencl-headers.
(rocminfo): Update to 5.6.0.
[arguments]: Use gexps.  Use search-input-file instead of assoc-ref and which.
(rocm-bandwidth-test): Update to 5.6.0.
[source]{patches}: Add fix-includes patch.
* gnu/packages/patches/rocm-comgr-3.1.0-dependencies.patch,
gnu/packages/patches/rocm-opencl-runtime-4.3-noclinfo.patch: Update patches.
* gnu/packages/patches/llvm-roc-4.0.0-remove-isystem-usr-include.patch,
gnu/packages/patches/llvm-roc-5.0.0-linkdl.patch,
gnu/packages/patches/rocm-opencl-runtime-4.3-noopencl.patch: Delete files.
* gnu/packages/patches/rocm-bandwidth-test-5.5.0-fix-includes.patch,
gnu/packages/patches/rocclr-5.6.0-enable-gfx800.patch: New files.
* gnu/local.mk (dist_patch_DATA): Update patches.
</span></span></td><td>John Kehayias</td></tr>