Issues when building ROOT with R statistics (ROOTR)

ROOT
9

@Axel Out of curiosity, I executed in the "<builddir>”:
cmake -DCMAKE_INSTALL_PREFIX=/tmp/root -P cmake_install.cmake
and then I found that three libraries in “ROOTSYS=/tmp/root” are broken.

ldd ${ROOTSYS}/lib/libRInterface.so
ldd ${ROOTSYS}/lib/libRMVA.so
ldd ${ROOTSYS}/lib/libRtools.so

report:
libRInside.so => not found
while for the same libraries in “ROOTSYS=<builddir>”, I get:
libRInside.so => /usr/lib/R/site-library/RInside/lib/libRInside.so

Manually executing:
export LD_LIBRARY_PATH="/usr/lib/R/site-library/RInside/lib:${LD_LIBRARY_PATH}"
fixes the problem and then the R tutorials work also when “ROOTSYS=/tmp/root”.