linux-user: Add separate aarch64_be uname

Make big-endian aarch64 systems identify as aarch64_be as expected by
big-endian userland and toolchains.
Signed-off-by: NMichael Weiser <michael.weiser@gmx.de>
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Reviewed-by: NLaurent Vivier <laurent@vivier.eu>
Message-id: 20171220212308.12614-3-michael.weiser@gmx.de
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

linux-user/aarch64/target_syscall.h

@@ -8,7 +8,11 @@ struct target_pt_regs {
     uint64_t        pstate;
 };
 
+#if defined(TARGET_WORDS_BIGENDIAN)
+#define UNAME_MACHINE "aarch64_be"
+#else
 #define UNAME_MACHINE "aarch64"
+#endif
 #define UNAME_MINIMUM_RELEASE "3.8.0"
 #define TARGET_CLONE_BACKWARDS
 #define TARGET_MINSIGSTKSZ       2048