Compile issues with GCC 11 / spack 0.17.0

[matz-e]

Hi,

When compiling

launchmon@master%[email protected]

with Spack 0.17.0, I get a lot of errors along the lines of

     329    In file included from ../../sdbg_rm_map.hxx:60,                                                                                                                                                                                  
     330                     from lmon_be_sync_mpi.cxx:47:                                                                                                                                                                                   
  >> 331    ../../sdbg_base_symtab.hxx:197:34: error: ISO C++17 does not allow dynamic exception specifications                                                                                                                              
     332      197 |   symtab_error_e compute_reloc() throw(symtab_exception_t);                                                                                                                                                              
     333          |                                  ^~~~~                                                                                                                                                                                   
  >> 334    ../../sdbg_base_symtab.hxx:203:47: error: ISO C++17 does not allow dynamic exception specifications                                                                                          
     335      203 |   symtab_error_e init(const std::string &lib) throw(symtab_exception_t);                                                                                                                                                 
     336          |                                               ^~~~~                                                                                                                                                                      
  >> 337    ../../sdbg_base_symtab.hxx:204:33: error: ISO C++17 does not allow dynamic exception specifications                                                                                                                              
     338      204 |   virtual symtab_error_e init() throw(symtab_exception_t) = 0;                                                                                                                                                           
     339          |                                 ^~~~~                                                                                                                                                                                    
  >> 340    ../../sdbg_base_symtab.hxx:205:49: error: ISO C++17 does not allow dynamic exception specifications                                                                                                                              
     341      205 |   virtual symtab_error_e read_linkage_symbols() throw(symtab_exception_t) = 0;                                                                                                                                           
     342          |                                                 ^~~~~                                                                                                                                                                    
  >> 343    ../../sdbg_base_symtab.hxx:207:49: error: ISO C++17 does not allow dynamic exception specifications                                                                                                                              
     344      207 |                                         bool &) throw(symtab_exception_t) = 0;                                                                                                                                           
     345          |                                                 ^~~~~                                                                                                                                                                    

Adding env.set('CXXFLAGS', '--std=c++14') to Spack's build environment leads to successful building, but ideally this flag should either be added to the autotools config, or the deprecated throw(…) be handled differently?