science/agrum: fix build on powerpc64 elfv2

LLD can't link this port on powerpc64 elfv2:
ld: error: relocation refers to a discarded section: .text._ZN3gum9ExceptionD2Ev

defined in src/CMakeFiles/agrum.dir/agrum/core/approximations/approximationScheme.cpp.o
section group signature: _ZN3gum9ExceptionD2Ev
prevailing definition is in src/CMakeFiles/agrum.dir/agrum/core/approximations/IApproximationSchemeConfiguration.cpp.o
referenced by approximationScheme.cpp

src/CMakeFiles/agrum.dir/agrum/core/approximations/approximationScheme.cpp.o:(gum::OutOfLowerBound::OutOfLowerBound(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >))

PR: 242804
Approved by: yuri (maintainer)