Found the following significant warnings:
  Warning: SystemRequirements: invalid C++ specification ‘C++ (>= 11)’
See ‘/home/hornik/tmp/R.check/r-devel-clang/Work/PKGS/MPCR.Rcheck/00install.out’ for details.
Found the following significant warnings:
  Warning: SystemRequirements: invalid C++ specification ‘C++ (>= 11)’
See ‘/home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/MPCR.Rcheck/00install.out’ for details.
Found the following significant warnings:
  Warning: SystemRequirements: invalid C++ specification ‘C++ (>= 11)’
See ‘/data/gannet/ripley/R/packages/tests-clang/MPCR.Rcheck/00install.out’ for details.
Found the following significant warnings:
  Warning: SystemRequirements: invalid C++ specification ‘C++ (>= 11)’
See ‘/data/gannet/ripley/R/packages/tests-devel/MPCR.Rcheck/00install.out’ for details.
Found the following significant warnings:
  Warning: SystemRequirements: invalid C++ specification ‘C++ (>= 11)’
See ‘/home/hornik/tmp/R.check/r-patched-gcc/Work/PKGS/MPCR.Rcheck/00install.out’ for details.
installed size is  5.6Mb
  sub-directories of 1Mb or more:
    libs   5.0Mb
installed size is  5.4Mb
  sub-directories of 1Mb or more:
    libs   4.8Mb