R for Windows 4.0.4

What's new in this version:

New:
- File share/texmf/tex/latex/jss.cls has been updated to work with LaTeX versions since Oct 2020
- Unicode character width tables (as used by nchar(, type = "w")) have been updated to Unicode 12.1
- The internal table for iswprint (used on Windows, macOS and AIX) has been updated to include many recent Unicode characters INSTALLATION on a UNIX-ALIKE If an external BLAS is specified by --with-blas=foo or _via_ environment variable BLAS_LIBS is not found, this is now a configuration error. The previous behaviour was not clear from
- the documentation: it was to continue the search as if with-blas=yes was specified

Fixed:
- all.equal(x,y) now "sees" the two different NAs in factors
- (NULL)[1] and similar formula subsetting now works. Additionally subsetting leaving an empty formula now works too
- traceback(n) keeps source references again, as before R 4.0.0 fixing a regression
- including two patch proposals by Brodie Gaslam
- unlist(plst, recursive=FALSE) no longer drops content for pairlists with list components
- iconvlist() now also works on MUSL based (Linux) systems
- round() and signif() no longer tolerate wrong argument names notably in 1-argument calls
- Machine has longdouble.* elements only if capabilities("long.double") is true, as documented. (Previously they were included if the platform had long double identical to double, as ARM does.)
- p.adjust(numeric(), n=0) now works
- identical(x,y) no longer prints "Unknown Type .." for typeof(x) "..." objects
- Fix (auto-)print()ing of named complex vectors
- all.equal(<language>, <...>) now works, fixing PR#18029
- as.data.frame.list(L, row.names=NULL) now behaves in line with data.frame(), disregarding names of components of L
- checkRdaFiles(ff)$version is now correct also when ff contains files of different versions