1) the output from rpmlint
=> unstripped-binary-or-object and dictionnary output are normal 

2) "License file installed when any subpackage combination is installed." that should be true but still minimize the number of duplicated files, please adjust the spec accordingly
=> fixed

3) Is the -devel package interesting without the main package?
=> No

4) I have a problem with: %{_defaultdocdir}/dsqlite could you explain what this is?
=>  explain the methods, this documentation is auto generated by any D compiler

5) The guidelines are refering to DFLAGS, while you are using DCFLAGS, any specific reasons? (see: https://fedoraproject.org/wiki/Packaging:D )
- Is there really no Requires for this package?
=> DCFLAGS is used as makefile provide only this var not  DFLAGS