Re-fix the detection of CPU architecture on an Apple OS

Commit d56c6cf7a4 was incorrect. It was a
nice try, but on a 64-bit Mac machine (x86_64 CPU), it returned
hw.cputype = 7, which is CPU_TYPE_X86. CPU_TYPE_X86_64 is only used in
Mach-O slices for fat binaries and does not reflect hw.cputype.

Task-number: QTBUG-61205
Change-Id: Ia3e896da908f42939148fffd14c54b3050b8e64b
Reviewed-by: Jake Petroules <jake.petroules@qt.io>

src/corelib/global/qglobal.cpp

@@ -86,12 +86,6 @@
 #  include <sys/systeminfo.h>
 #endif
 
-#if defined(Q_OS_DARWIN)
-#  include <mach/machine.h>
-#  include <sys/sysctl.h>
-#  include <sys/types.h>
-#endif
-
 #ifdef Q_OS_UNIX
 #include <sys/utsname.h>
 #include <private/qcore_unix_p.h>
@@ -2443,20 +2437,9 @@ QString QSysInfo::currentCpuArchitecture()
     case PROCESSOR_ARCHITECTURE_IA64:
         return QStringLiteral("ia64");
     }
-#elif defined(Q_OS_DARWIN)
-    cpu_type_t type;
-    size_t size = sizeof(type);
-    sysctlbyname("hw.cputype", &type, &size, NULL, 0);
-    switch (type) {
-    case CPU_TYPE_X86:
-        return QStringLiteral("i386");
-    case CPU_TYPE_X86_64:
-        return QStringLiteral("x86_64");
-    case CPU_TYPE_ARM:
-        return QStringLiteral("arm");
-    case CPU_TYPE_ARM64:
-        return QStringLiteral("arm64");
-    }
+#elif defined(Q_OS_DARWIN) && !defined(Q_OS_MACOS)
+    // iOS-based OSes do not return the architecture on uname(2)'s result.
+    return buildCpuArchitecture();
 #elif defined(Q_OS_UNIX)
     long ret = -1;
     struct utsname u;