Log message:
textproc: Replace RMD160 checksums with BLAKE2s checksums

All checksums have been double-checked against existing RMD160 and
SHA512 hashes

Unfetchable distfiles (fetched conditionally?):
./textproc/convertlit/distinfo clit18src.zip

Log message:
textproc: Remove SHA1 hashes for distfiles

Log message:
Update all R packages to canonical form.

The canonical form [1] of an R package Makefile includes the
following:

- The first stanza includes R_PKGNAME, R_PKGVER, PKGREVISION (as
  needed), and CATEGORIES.

- HOMEPAGE is not present but defined in math/R/Makefile.extension to
  refer to the CRAN web page describing the package.  Other relevant
  web pages are often linked from there via the URL field.

This updates all current R packages to this form, which will make
regular updates _much_ easier, especially using pkgtools/R2pkg.

[1] http://mail-index.netbsd.org/tech-pkg/2019/08/02/msg021711.html

Log message:
Remove MASTER_SITES= from individual R package Makefiles.

Each R package should include ../../math/R/Makefile.extension, which also
defines MASTER_SITES.  Consequently, it is redundant for the individual
packages to do the same.  Package-specific definitions also prevent
redefining MASTER_SITES in a single common place.

Log message:
Import textproc/R-gsubfn 0.6-6 into pkgsrc.

gsubfn is like gsub but can take a replacement function or certain
other objects instead of the replacement string. Matches and back
references are input to the replacement function and replaced by
the function output.