SIGEMT is not defined everywhere e.g musl does
not define it. Therefore check it being defined
before using it.

Fixes errors e.g.
../../strace-4.13/tests/signal2name.c:45:7: error: 'SIGEMT' undeclared (first use in this function)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Upstream-Status: Pending

Index: strace-4.13/tests/signal2name.c
===================================================================
--- strace-4.13.orig/tests/signal2name.c
+++ strace-4.13/tests/signal2name.c
@@ -42,7 +42,9 @@ signal2name(int sig)
 	CASE(SIGEMT);
 	CASE(SIGLOST);
 #elif defined MIPS
+#ifdef SIGEMT
 	CASE(SIGEMT);
+#endif
 	CASE(SIGIOT);
 	CASE(SIGPWR);
 #else