Log Message:
(math/R-ncdf4) Updated 1.17 to 1.21

Release 1.21 (2023-01-05) Minor change to fix compatibility with
latest version of R (removed C lang sprintf). Another small update
to libraries linked for windows by request of Tomas Kalibera.

Release 1.20 (2022-11-30) Small warning message bug fix (thank you
to Javier Vaquero-Martinez!) and updates to windows Makefile requested by
CRAN (Tomas Kalibera).

Release 1.19 (2021-12-14) Changed as per request of R developers
to build correctly on Windows using the new R toolchain (Rtools42).
Specifically, added the supplided Makevars.ucrt to src/.

Release 1.18 (2021-11-17) Fixed a bug in the way files with
complicated nested groups were processed.