c++17 compiler needed

[dsschult]

From a test on an (older) custom compiler on a supercomputer. Apparently there is no test in cmake, but the code requires c++17.

[ 24%] Building CXX object CMakeFiles/cphotospline.dir/src/cinter/splinetable.cpp.o
/opt/intel/compilers_and_libraries_2020.1.217/linux/bin/intel64/icpc -DPHOTOSPLINE_VERSION=2.1.0 -Dcphotospline_EXPORTS -I/work2/00434/eijkhout/icecube/photospline/photospline-git/include -I/work2/00434/eijkhout/icecube/cfitsio/installation-4.1.0-clx/include -fPIC   -I/work2/00434/eijkhout/icecube/cfitsio/installation-4.1.0-clx/include -ISUITESPARSE_INCLUDE_DIR-NOTFOUND -Wall -Wextra -O3 -msse2 -msse3 -msse4 -msse4.1 -msse4.2 -mno-avx -std=gnu++11 -MD -MT CMakeFiles/cphotospline.dir/src/cinter/splinetable.cpp.o -MF CMakeFiles/cphotospline.dir/src/cinter/splinetable.cpp.o.d -o CMakeFiles/cphotospline.dir/src/cinter/splinetable.cpp.o -c /work2/00434/eijkhout/icecube/photospline/photospline-git/src/cinter/splinetable.cpp
/work2/00434/eijkhout/icecube/photospline/photospline-git/include/photospline/detail/simd.h(31): internal error: assertion failed at: "shared/cfe/edgcpfe/overload.c", line 24602

                a = b - type{};
                              ^

[cnweaver]

This code hasn't changed in years, and given that it builds with g++ 4.8.5, I think it's more likely that whatever this compiler is it doesn't fully implement this gcc extension.

[dsschult]

Looks like an intel compiler. Also note I'm just reporting this from another person we're working with at TACC.