Missing /usr/lib64 in default search paths

[Flamefire]

I ran into trouble caused by libtool adding /usr/lib64 to the rpath of a library.

sys_lib_dlsearch_path_spec seems to be intended to avoid adding default paths to rpath. For Linux (linux-gnu) it is set here:

libtool/m4/libtool.m4

Line 2956 in 5586070

sys_lib_dlsearch_path_spec="/lib /usr/lib $lt_ld_extra"

However this misses /usr/lib64 and only adds /usr/lib

I don't see that folder in ldconf.so but in ld --verbose:

$  ld --verbose | grep SEARCH_DIR
SEARCH_DIR("=/usr/x86_64-redhat-linux/lib64"); SEARCH_DIR("=/usr/lib64"); SEARCH_DIR("=/usr/local/lib64"); SEARCH_DIR("=/lib64"); SEARCH_DIR("=/usr/x86_64-redhat-linux/lib"); SEARCH_DIR("=/usr/local/lib"); SEARCH_DIR("=/lib"); SEARCH_DIR("=/usr/lib");

Is that intentional or an oversight?
Can this be fixed/workarounded without changing the source?