Doxygen in textproc/libe-book Makefile

[Sid]

Proposal to change DOCS to DOXYGEN in textproc/libe-book/Makefile, because it is defined in /usr/ports/Mk/bsd.options.desc.mk
It better describes the option, and it allows for conformity in choosing types of documentation used, especially from make.conf.

textproc/libe-book/Makefile

19c19
< OPTIONS_DEFINE=       DOCS
---
> OPTIONS_DEFINE=       DOXYGEN
31,32c31,32
< DOCS_BUILD_DEPENDS=   doxygen:devel/doxygen
< DOCS_CONFIGURE_OFF=   --without-docs
---
> DOXYGEN_BUILD_DEPENDS=        doxygen:devel/doxygen
> DOXYGEN_CONFIGURE_OFF=        --without-doxygen


Thank you