teach linux build to distinguish 32- and 64-bit erlang
teach linux build to distinguish 32- and 64-bit erlang

Change Linux build to check whether the Erlang system available is
32-bit or 64-bit and use the right build flags for c_src to
match. This support is mostly the same as changes added some time ago
to distinguish 32- and 64-bit builds on OS X.

Also change configure script to use "host" where "target" used to be
used, since according to autotools documentation "host" is what was
really meant.

jgrinstead/yaws,bsmr-erlang/yaws,phonohawk/yaws,toraritte/azith,patternmatched/yaws,capflam/yaws,toraritte/azith,watonyweng/yaws,jgrinstead/yaws,toraritte/azith,phonohawk/yaws,sebgod/yaws,leoliu/yaws,capflam/yaws,klacke/yaws,weisslj/yaws,leoliu/yaws,phonohawk/yaws,leoliu/yaws,klacke/yaws,patternmatched/yaws,andreineculau/yaws,namjae/yaws,weisslj/yaws,bsmr-erlang/yaws,zephyrean/yaws,jgrinstead/yaws,namjae/yaws,phonohawk/yaws,toraritte/azith,sebgod/yaws,namjae/yaws,watonyweng/yaws,leoliu/yaws,capflam/yaws,treacheroustalks/yaws,capflam/yaws,capflam/yaws,patternmatched/yaws,watonyweng/yaws,bsmr-erlang/yaws,klacke/yaws,imtal/yaws,sebgod/yaws,leoliu/yaws,andreineculau/yaws,namjae/yaws,klacke/yaws,bsmr-erlang/yaws,ca91/yaws,phonohawk/yaws,ca91/yaws,zephyrean/yaws,ca91/yaws,watonyweng/yaws,ca91/yaws,andreineculau/yaws,zephyrean/yaws,jgrinstead/yaws,klacke/yaws,klacke/yaws,ca91/yaws,phonohawk/yaws,treacheroustalks/yaws,imtal/yaws,treacheroustalks/yaws,watonyweng/yaws,jgrinstead/yaws,bsmr-erlang/yaws,jgrinstead/yaws,imtal/yaws,watonyweng/yaws,weisslj/yaws,imtal/yaws,namjae/yaws,weisslj/yaws,ca91/yaws,andreineculau/yaws,toraritte/azith,capflam/yaws,sebgod/yaws,sebgod/yaws,toraritte/azith,andreineculau/yaws,imtal/yaws,weisslj/yaws,leoliu/yaws,namjae/yaws,imtal/yaws,patternmatched/yaws,imtal/yaws,treacheroustalks/yaws,phonohawk/yaws,patternmatched/yaws,capflam/yaws,namjae/yaws,patternmatched/yaws,toraritte/azith,leoliu/yaws,klacke/yaws,sebgod/yaws,patternmatched/yaws,bsmr-erlang/yaws,weisslj/yaws,watonyweng/yaws,sebgod/yaws,zephyrean/yaws,zephyrean/yaws,zephyrean/yaws,zephyrean/yaws,weisslj/yaws,ca91/yaws,jgrinstead/yaws,bsmr-erlang/yaws