added suppression for mysterious DL linker issues

tests/sigaltstack.suppression

@@ -6,3 +6,71 @@
    fun:install_stack_overflow_handler
 }
 
+{
+   mysterious_dl_leak_1
+   Memcheck:Leak
+   match-leak-kinds: reachable
+   fun:malloc
+   fun:strdup
+   fun:_dl_load_cache_lookup
+   fun:_dl_map_object
+   fun:dl_open_worker
+   fun:_dl_catch_exception
+   fun:_dl_open
+   fun:do_dlopen
+   fun:_dl_catch_exception
+   fun:_dl_catch_error
+   fun:dlerror_run
+   fun:__libc_dlopen_mode
+}
+{
+   mysterious_dl_leak_2
+   Memcheck:Leak
+   match-leak-kinds: reachable
+   fun:malloc
+   fun:_dl_new_object
+   fun:_dl_map_object_from_fd
+   fun:_dl_map_object
+   fun:dl_open_worker
+   fun:_dl_catch_exception
+   fun:_dl_open
+   fun:do_dlopen
+   fun:_dl_catch_exception
+   fun:_dl_catch_error
+   fun:dlerror_run
+   fun:__libc_dlopen_mode
+}
+{
+   mysterious_dl_leak_3
+   Memcheck:Leak
+   match-leak-kinds: reachable
+   fun:calloc
+   fun:_dl_check_map_versions
+   fun:dl_open_worker
+   fun:_dl_catch_exception
+   fun:_dl_open
+   fun:do_dlopen
+   fun:_dl_catch_exception
+   fun:_dl_catch_error
+   fun:dlerror_run
+   fun:__libc_dlopen_mode
+   fun:pthread_cancel_init
+   fun:_Unwind_ForcedUnwind
+}
+{
+   mysterious_dl_leak_4
+   Memcheck:Leak
+   match-leak-kinds: reachable
+   fun:calloc
+   fun:_dl_new_object
+   fun:_dl_map_object_from_fd
+   fun:_dl_map_object
+   fun:dl_open_worker
+   fun:_dl_catch_exception
+   fun:_dl_open
+   fun:do_dlopen
+   fun:_dl_catch_exception
+   fun:_dl_catch_error
+   fun:dlerror_run
+   fun:__libc_dlopen_mode
+}