[RDY] Initial Cleanup Round 1

Continuing from Round 0 (#315)

 * blowfish.c
 * charset.c 
 * crypt.c
 * diff.c
 * digraph.c
 * garray.c/h
 * hashtab.c
 * popupmnu.c
 * sha256.c
 * version.c

Overall progress tracked in #311