[PATCH 06/13] sim/m32r: fix unused function warnings on non-Linux hosts

When building on macOS, I get:

    /Users/smarchi/src/binutils-gdb/sim/m32r/traps.c:141:1: error: unused function 't2h_addr' [-Werror,-Wunused-function]
      141 | t2h_addr (host_callback *cb, struct cb_syscall *sc,
          | ^~~~~~~~
    /Users/smarchi/src/binutils-gdb/sim/m32r/traps.c:158:1: error: unused function 'translate_endian_h2t' [-Werror,-Wunused-function]
      158 | translate_endian_h2t (void *addr, size_t size)
          | ^~~~~~~~~~~~~~~~~~~~
    /Users/smarchi/src/binutils-gdb/sim/m32r/traps.c:171:1: error: unused function 'translate_endian_t2h' [-Werror,-Wunused-function]
      171 | translate_endian_t2h (void *addr, size_t size)
          | ^~~~~~~~~~~~~~~~~~~~

These three helpers are only called from the TRAP_LINUX_SYSCALL case,
which is guarded by `#ifdef __linux__'.  Put them behind the same guard.

Change-Id: I8c8744727eb27abc08231be2a10f8d0de44d7ea6
---
 sim/m32r/traps.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/sim/m32r/traps.c b/sim/m32r/traps.c
index bb82ae80e2aa..43a81c915d1c 100644
--- a/sim/m32r/traps.c
+++ b/sim/m32r/traps.c
@@ -134,7 +134,9 @@ m32r_core_signal (SIM_DESC sd, SIM_CPU *current_cpu, sim_cia cia,
     sim_core_signal (sd, current_cpu, cia, map, nr_bytes, addr,
 		     transfer, sig);
 }
-
+
+#ifdef __linux__
+
 /* Translate target's address to host's address.  */
 
 static void *
@@ -180,6 +182,8 @@ translate_endian_t2h (void *addr, size_t size)
     *((unsigned short *) p) = T2H_2 (*((unsigned short *) p));
 }
 
+#endif /* __linux__ */
+
 /* Trap support.
    The result is the pc address to continue at.
    Preprocessing like saving the various registers has already been done.  */
-- 
2.55.0