S/390: Add undef for MUSL_DYNAMIC_LINKERxx

This fixes the s390 bootstrap by undefining existing defines before
redefining them.


gcc/ChangeLog:

2019-11-26  Robin Dapp  <rdapp@linux.ibm.com>

  * config/s390/linux.h: Add undef for MUSL_DYNAMIC_LINKERxx.

From-SVN: r278721

gcc/ChangeLog

+2019-11-26  Robin Dapp  <rdapp@linux.ibm.com>
+
+	* config/s390/linux.h: Add undef for MUSL_DYNAMIC_LINKERxx.
+
 2019-11-26  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/92644

gcc/config/s390/linux.h

@@ -75,7 +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"
 
+#undef MUSL_DYNAMIC_LINKER32
 #define MUSL_DYNAMIC_LINKER32 "/lib/ld-musl-s390.so.1"
+#undef MUSL_DYNAMIC_LINKER64
 #define MUSL_DYNAMIC_LINKER64 "/lib/ld-musl-s390x.so.1"
 
 #undef  LINK_SPEC