I'm trying to follow these instructions to compile Elmer FEM on macOS Mojave Version 10.14.6 . However, when running the make install I get the error message:

.../elmerfem/umfpack/src/umfpack/include/umf_internal.h:29:10: fatal error: 'string.h' file not found #include <string.h> ^~~~~~~~~~ 1 error generated. make[2]: *** [umfpack/src/umfpack/umfpack_zl_save_symbolic.c] Error 1 make[2]: *** Deleting file `umfpack/src/umfpack/umfpack_zl_save_symbolic.c' make[1]: *** [umfpack/src/umfpack/CMakeFiles/umfpack.dir/all] Error 2 make: *** [all] Error 2

searching the internet this post suggests

xcode-select --install

sudo xcode-select --switch /Library/Developer/CommandLineTools/

which had already been done before in my case and have no effect on the above error. This and this post suggest

sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target / -allowUntrusted

which leads to the error message

installer: The install failed (The Installer encountered an error that caused the installation to fail. Contact the software manufacturer for assistance.)

I would appreciate it if you could help me know what is the problem and how I can resolve it. Thanks for your kind support in advance.

P.S.1. As was asked here, my make version is GNU Make 3.81 .

P.S.2. the list of string.h files on my hard drive here.

P.S.3. the output of CMake is pasted here.