libxo-1.7.4

• Add xo_default_init_utf8 to work about a clang bug
• Add xo_safe_va_arg_long_double to work around a gcc bug
• Fix initialization of xo_eval_value values
• Make my own XO_HOST_NAME_MAX since linux doesn't seem to have it and the gethostname man page says it useless anyway
• add some fancy casts to avoid a missing symbol (__divti3) for gcc/mips
• more yytname and yypact defines higher in the file, since bison needs to earlier that byacc; comment out dup token for L_ASTERISK