Update to 2.16.0

• Remove @MASTERSITES_WHITELIST
• Remove some remnants of multi-OS support: always false conditions and unused variables ($automan, $autoinfo, $manstrict, $mancompress, $multiplist, $newxdef, $rcsidinplist, $ldconfigwithtrue)
• Remove check for USE_SIZE
• Remove check for 'Version Required' in header
• Remove pkgtools remnants: fix pkg_version invocations, remove check for PKGINSTALLVER, remove check for old packages in $portsdir
• Update check for IGNOREFILES macro
• Remove comment about EXEC_DEPENDS
• Remove check for NO_CONFIGURE/NO_PATCH
• Remove '@dirrm for %%DOCSDIR%%' check
• Remove pkg-comment check
• Remove check for /usr/X11R6
• Remove check for gcc_val 3.x and 4.1 conditions
• STAGE is now required
• Remove MANLANG check
• Add NOPORTEXAMPLES/NOPORTDOCS deprecation warning
• Add @stopdaemon, @cwd deprecation warning
• Add PLIST_DIRSTRY deprecation warning
• Add check for make :L :U modifiers
• Add check for for MAN[1-9] macro
• Allow use of absolute path in plist
• Fix checks for EXTRACT_SUFX
• Fix USE_ANT and USES=gmake warning
• Convert WITH(OUT)_$1 to PORT_OPTIONS:M$1 in warning
• Convert USE_DOS2UNIX to USES=dos2unix in warning
• Convert USE_ZIP to USES=zip in EXTRACT_SUFX check
• Convert USE_PERL5 to USES=perl5 in warning
• Convert USE_ICONV to USES=iconv in warning
• Modify checkplist() to accept @fc/@shell/other new keywords

PR: 194285
Submitted by: ak