Fix xmessage handling in assert.cc

The return value of the system call is not directly the exit value
of the process, but a status that needs to be inspected with some
macros.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/assert.cc b/src/assert.cc
index 5f8a3f9d..4b7c180a 100644
--- a/src/assert.cc
+++ b/src/assert.cc
@@ -32,7 +32,8 @@ bool notify_fatal_error(StringView msg)
                       MB_OKCANCEL | MB_ICONERROR) == IDOK;
 #elif defined(__linux__)
     auto cmd = format("xmessage -buttons 'quit:0,ignore:1' '{}'", msg);
-    return system(cmd.c_str()) == 1;
+    int status = system(cmd.c_str());
+    return (WIFEXITED(status)) ? (WEXITSTATUS(status)) == 1 : false;
 #endif
 }