* installing *source* package ‘cplexAPI’ ...
** package ‘cplexAPI’ successfully unpacked and MD5 sums checked
** using staged installation
'config' variable 'CPP' is deprecated
checking for gcc... clang -mmacosx-version-min=10.13
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 -mmacosx-version-min=10.13 accepts -g... yes
checking for clang -mmacosx-version-min=10.13 option to accept ISO C89... none needed
checking how to run the C preprocessor... clang -mmacosx-version-min=10.13 -E
checking for cplex... NONE
configure: error: CPLEX interactive optimizer not found
ERROR: configuration failed for package ‘cplexAPI’
* removing ‘/Volumes/Builds/packages/high-sierra-x86_64/results/4.0/cplexAPI.Rcheck/cplexAPI’