VoxForge
My 'make all' (OpenSUSE 11.4) stopped with an error about spaces and tabs in a Makefile.
It was line 77 in HLMTools/Makefile - I edited this file to replace a bunch of spaces with a tab at the beginning of that line and now it works. I think you have to do this each time you do a configure since Makefile is autogenerated each time.
gcc 4.5 works no problem on this version of HTK.