I've rebuilt ttmkfdir-3.0.7 on rh7.3 and all it does is segfault when trying to process *any* fonts, including those in XFree86-truetype-fonts.
Further testing shows it is apparently a compiler/optimizing bug compiling parser.cpp. I was building using -Os. Using any of -O0, -O1, -O2 works fine. For fun, I'm attaching a patch that eliminates a compiler warning in ttf.cpp.
Created attachment 89527 [details] Hushes compiler warning about empty return;
ttmkfdir is using RPM_OPT_FLAGS which is set by rpm, if you build the source directly, you might have that problem, I can try to use autoconf/automake if really needed.
We do not officially support recompilation of current generation software in older releases of Red Hat Linux. There are enough bugs/problems to fix in software going forward than to make all current generation software also compile in older releases as well. If someone can post a patch that resolves the problem, if it is indeed a bug, then I'm sure we'll apply it as long as it does not cause problems with the current ttmkfdir in rawhide, however it would be IMHO an extremely low priority thing to look at. My personal inclination is just to close this WONTFIX->UNSUPPORTED but it's not my package so It's Yu Shao's call.
close it for now, please reopen if needed.