Compilation error: stdlib.h

[vitduck]

OS: Ubuntu 18.04
GCC: 7.5
ROCM: 5.1.3
GPU: MI200

1. Steps to reproduce:

mkdir build 
cmake .. -DGMX_GPU_USE_AMD=on -DGMX_BUILD_OWN_FFTW=ON  -DCMAKE_CXX_FLAGS="-I/usr/include"
make 

2. Error message:

[  1%] Building CXX object src/programs/CMakeFiles/mdrun_objlib.dir/mdrun/mdrun.cpp.o
cd [...] && /usr/bin/c++ -DGMX_DOUBLE=0 -DHAVE_CONFIG_H -I/global/home/tyhong/build/src/gromacs-rocm/build/src/external/build-fftw/fftwBuild-prefix/include -I/global/home/tyhong/build/src/gromacs-rocm/build/src -I/global/home/tyhong/build/src/gromacs-rocm/src -isystem /global/home/tyhong/build/src/gromacs-rocm/src/external/thread_mpi/include -isystem /usr/include -I/usr/include -O3 -DNDEBUG -mavx2 -mfma -Wall -Wextra -Wno-missing-field-initializers -Wpointer-arith -Wmissing-declarations -Wundef -fexcess-precision=fast -funroll-all-loops -Wno-array-bounds -std=c++14 -o CMakeFiles/mdrun_objlib.dir/mdrun/mdrun.cpp.o -c /global/home/tyhong/build/src/gromacs-rocm/src/programs/mdrun/mdrun.cpp
In file included from /usr/include/c++/7/ext/string_conversions.h:41:0,
                 from /usr/include/c++/7/bits/basic_string.h:6361,
                 from /usr/include/c++/7/string:52,
                 from /usr/include/c++/7/stdexcept:39,
                 from /usr/include/c++/7/array:39,
                 from /usr/include/c++/7/tuple:39,
                 from /usr/include/c++/7/bits/unique_ptr.h:37,
                 from /usr/include/c++/7/memory:80,
                 from /global/home/tyhong/build/src/gromacs-rocm/src/programs/mdrun/mdrun.cpp:57:
/usr/include/c++/7/cstdlib:75:15: fatal error: stdlib.h: No such file or directory
 #include_next <stdlib.h>
               ^~~~~~~~~~
compilation terminated.

Actually the C stdlib.h is already located under /usr/include.

$ ls /usr/include/stdlib.h
/usr/include/stdlib.h

I not sure why it was not picked up.
Please kindly advise.