Follow up 14714: use a real malloc cost centre instead of an empty string


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14715 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/coregrind/m_main.c b/coregrind/m_main.c
index 4039558..6542600 100644
--- a/coregrind/m_main.c
+++ b/coregrind/m_main.c
@@ -599,7 +599,7 @@
                nextpos = startpos + VG_(strlen)(startpos);
             if (startpos != nextpos) {
                VG_(clo_error_markers)[m] 
-                  = VG_(malloc)("", nextpos - startpos + 1);
+                  = VG_(malloc)("main.mpclo.2", nextpos - startpos + 1);
                VG_(memcpy)(VG_(clo_error_markers)[m], startpos, 
                            nextpos - startpos);
                VG_(clo_error_markers)[m][nextpos - startpos] = '\0';