Error(s) in re-building vignettes:
--- re-building ‘external.programs.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'external.programs.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘external.programs.Rmd’

--- re-building ‘gtypes.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'gtypes.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘gtypes.Rmd’

--- re-building ‘population.structure.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'population.structure.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘population.structure.Rmd’

--- re-building ‘sequences.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'sequences.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘sequences.Rmd’

--- re-building ‘summaries.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'summaries.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘summaries.Rmd’

SUMMARY: processing the following files failed:
  ‘external.programs.Rmd’ ‘gtypes.Rmd’ ‘population.structure.Rmd’
  ‘sequences.Rmd’ ‘summaries.Rmd’

Error: Vignette re-building failed.
Execution halted