Use uname -p to detect x86_64 on QNX.

mesonbuild/environment.py

@@ -337,7 +337,7 @@ def detect_cpu_family(compilers: CompilersDict) -> str:
     """
     if mesonlib.is_windows():
         trial = detect_windows_arch(compilers)
-    elif mesonlib.is_freebsd() or mesonlib.is_netbsd() or mesonlib.is_openbsd():
+    elif mesonlib.is_freebsd() or mesonlib.is_netbsd() or mesonlib.is_openbsd() or mesonlib.is_qnx():
         trial = platform.processor().lower()
     else:
         trial = platform.machine().lower()

mesonbuild/mesonlib.py

@@ -527,6 +527,8 @@ def is_irix() -> bool:
 def is_hurd() -> bool:
     return platform.system().lower() == 'gnu'
 
+def is_qnx() -> bool:
+    return platform.system().lower() == 'qnx'
 
 def exe_exists(arglist: T.List[str]) -> bool:
     try: