Make the `input` code into a library function in dlib

[dplassgit]

d2lang/src/com/plasstech/lang/d2/codegen/x64/InputCodeGenerator.java

Line 47 in 44f44fb

emitter.emit("mov RDX, %d; allocate 1mb", ONE_MB);

[dplassgit]

Right now it inlines this code everywhere it's used (though it's unlikely input is called more than once per file.)

This influences #382