s390: add musl support

Add the musl dynamic linker names.

gcc/ChangeLog:

2019-11-18  Szabolcs Nagy  <szabolcs.nagy@arm.com>

	* config/s390/linux.h (MUSL_DYNAMIC_LINKER32): Define.
	(MUSL_DYNAMIC_LINKER64): Define.

From-SVN: r278397

gcc/ChangeLog

+2019-11-18  Szabolcs Nagy  <szabolcs.nagy@arm.com>
+
+	* config/s390/linux.h (MUSL_DYNAMIC_LINKER32): Define.
+	(MUSL_DYNAMIC_LINKER64): Define.
+
 2019-11-18  Martin Liska  <mliska@suse.cz>
 
 	* dbgcnt.c (dbg_cnt_set_limit_by_name): Provide error

gcc/config/s390/linux.h

@@ -75,6 +75,9 @@ along with GCC; see the file COPYING3.  If not see
 #define GLIBC_DYNAMIC_LINKER32 "/lib/ld.so.1"
 #define GLIBC_DYNAMIC_LINKER64 "/lib/ld64.so.1"
 
+#define MUSL_DYNAMIC_LINKER32 "/lib/ld-musl-s390.so.1"
+#define MUSL_DYNAMIC_LINKER64 "/lib/ld-musl-s390x.so.1"
+
 #undef  LINK_SPEC
 #define LINK_SPEC \
   "%{m31:-m elf_s390}%{m64:-m elf64_s390} \