[PATCH v2] linux-user/syscall.c: fix build without RLIMIT_RTTIME

[Fabrice Fontaine]

RLIMIT_RTTIME is not provided by uclibc-ng or by musl prior to version
1.2.0 and
https://github.com/bminor/musl/commit/2507e7f5312e79620f6337935d0a6c9045ccba09
resulting in the following build failure since
https://git.qemu.org/?p=qemu.git;a=commit;h=244fd08323088db73590ff2317dfe86f810b51d7:

../linux-user/syscall.c: In function 'target_to_host_resource':
../linux-user/syscall.c:1057:16: error: 'RLIMIT_RTTIME' undeclared (first use 
in this function); did you mean 'RLIMIT_NOFILE'?
 1057 |         return RLIMIT_RTTIME;
      |                ^~~~~~~~~~~~~
      |                RLIMIT_NOFILE

Fixes:
 - 
http://autobuild.buildroot.org/results/22d3b584b704613d030e1ea9e6b709b713e4cc26

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
Changes v1 -> v2 (after review of Laurent Vivier):
 - Use an ifdef block instead of defining RLIMIT_RTTIME

 linux-user/syscall.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index dd0d92ba4e..488facb356 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -1053,8 +1053,10 @@ static inline int target_to_host_resource(int code)
         return RLIMIT_RSS;
     case TARGET_RLIMIT_RTPRIO:
         return RLIMIT_RTPRIO;
+#ifdef RLIMIT_RTTIME
     case TARGET_RLIMIT_RTTIME:
         return RLIMIT_RTTIME;
+#endif
     case TARGET_RLIMIT_SIGPENDING:
         return RLIMIT_SIGPENDING;
     case TARGET_RLIMIT_STACK:
-- 
2.35.1