* installing *source* package 'cplexAPI' ...
** package 'cplexAPI' successfully unpacked and MD5 sums checked
** using staged installation
** libs

*** arch - i386
make[1]: Entering directory '/d/temp/RtmpEXqCDu/R.INSTALL1d1ec512d2bc4/cplexAPI/src-i386'
d:/Compiler/rtools40/mingw32/bin/gcc  -I"D:/RCompile/recent/R4/include" -DNDEBUG -g -D_R_=1 -DUSE_R=1 -I"\cplex\include"    -I"d:/Compiler/gcc-4.9.3/local330/include"     -pedantic -O2 -Wall  -std=gnu99 -mfpmath=sse -msse2 -mstackrealign -c cplexAPI.c -o cplexAPI.o
In file included from cplexAPI.h:26,
                 from cplexAPI.c:26:
cplexR.h:50:10: fatal error: ilcplex/cplex.h: No such file or directory
 #include <ilcplex/cplex.h>
          ^~~~~~~~~~~~~~~~~
compilation terminated.
make[1]: *** [D:/RCompile/recent/R4/etc/i386/Makeconf:217: cplexAPI.o] Error 1
make[1]: Leaving directory '/d/temp/RtmpEXqCDu/R.INSTALL1d1ec512d2bc4/cplexAPI/src-i386'
ERROR: compilation failed for package 'cplexAPI'
* removing 'd:/Rcompile/CRANpkg/lib/4.0gcc8/cplexAPI'