fix default build when getpass() is unavailable if the system doesn't support getpass, we still default on the options that require it which causes a build failure. instead, only default enable these when getpass is available.

Tech Note #7
Quick building for testing with LTM

EXTRALIBS=-ltommath CFLAGS="-g3 -DLTC_NO_ASM -DUSE_LTM -DLTM_DESC" make -j3 IGNORE_SPEED=1 test