math/lcalc: Improve port

• Change PORTVERSION --> DISTVERSION
• Update MASTER_SITES
• Define LICENSE_FILE
• Drop USES= autoreconf
• Fix LIB_DEPENDS
• Remove GITLAB variables
• Define --with-pkgconfigdir
• Minor layout changes in Makefile to closer follow Porters Handbook

Source:
https://github.com/sagemath/sage/releases/download/10.6/mirror_list

PR: 286540
Approved by: maintainer timeout, 2+ weeks