Build file templates: additional information to build file template functions

Send a bit information to the build file template functions.  For
src2obj(), the additional option 'product' holds the name of the final
file that the object file will go into.  Additionally, the diverse
functions will get the option 'installed', with a value that evaluates
true if the final product is to be installed, otherwise false.

Reviewed-by: Rich Salz <rsalz@openssl.org>