math/galculator: Update to 2.1.4

• Follow upstream move from SF to GitHub, and new website hosting
• Add USES=autoreconf libtool as GH tarball only comes with configure.ac
• Add OPTIONS to select GTK3 or GTK2 (GTK3 by default as per upstream)
• Add USE_GNOME=cairo und GTK2_LIB_DEPENDS undeclared dependencies

Changes this release:

https://github.com/galculator/galculator/blob/v2.1.4/ChangeLog

Reviewed by: adamw (mentor)
Approved by: naddy (maintainer), mat (mentor)
Differential Revision: https://reviews.freebsd.org/D7789