* installing *source* package ‘Rmpi’ ...
** package ‘Rmpi’ successfully unpacked and MD5 sums checked
** using staged installation
checking for gcc... clang -arch x86_64
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables... 
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether clang -arch x86_64 accepts -g... yes
checking for clang -arch x86_64 option to accept ISO C89... none needed
checking for pkg-config... /opt/R/x86_64/bin/pkg-config
checking if pkg-config knows about OpenMPI... no
checking how to run the C preprocessor... clang -arch x86_64 -E
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
checking for ANSI C header files... rm: conftest.dSYM: is a directory
rm: conftest.dSYM: is a directory
yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking mpi.h usability... no
checking mpi.h presence... no
checking for mpi.h... no
configure: error: "Cannot find mpi.h header file"
ERROR: configuration failed for package ‘Rmpi’
* removing ‘/Volumes/Builds/packages/big-sur-x86_64/results/4.4/Rmpi.Rcheck/Rmpi’