The following is in src/CMakeLists.txt, and it seems like the *else* will never trigger and "pki_crypto.c" will never be included:
if (WITH_GCRYPT) set(libssh_SRCS ${libssh_SRCS} libgcrypt.c gcrypt_missing.c pki_gcrypt.c ) else (WITH_GCRYPT) set(libssh_SRCS ${libssh_SRCS} pki_crypto.c ) endif (WITH_GCRYPT) Dustin