add cran-comments for 6.0.0

Author: kevinushey

.Rbuildignore

@@ -19,4 +19,5 @@
 ^tools/tbb$
 ^\.github$
 ^\.claude$
+^cran-comments\.md$
 ^patches

cran-comments.md

@@ -0,0 +1,28 @@
+## RcppParallel 6.0.0
+
+This is a major release, which updates the bundled version of oneTBB to
+2022.0.0. Because the TBB ABI has changed, packages compiled against an
+older version of RcppParallel may need to be rebuilt. RcppParallel provides
+compatibility headers and symbols to help ease this transition.
+
+On Windows, RcppParallel now uses the copy of TBB provided by Rtools
+(R >= 4.2.0), rather than bundling its own copy.
+
+## R CMD check results
+
+0 errors | 0 warnings | 0 notes
+
+## revdepcheck results
+
+We checked 301 reverse dependencies (273 from CRAN + 28 from Bioconductor),
+comparing R CMD check results across CRAN and dev versions of this package.
+
+ * We saw 0 new problems
+ * We failed to check 16 packages
+
+The packages we failed to check did so because they link, directly or
+transitively, against other packages (e.g. 'Rfast', 'stringfish') that were
+themselves compiled against the previous TBB ABI. These fail to load with
+errors such as "undefined symbol: _ZTIN3tbb4taskE" until those upstream
+packages are rebuilt against oneTBB 2022.0. We expect these to resolve once
+CRAN rebuilds the reverse dependency chain against RcppParallel 6.0.0.