-

vagrant@vagrant-ubuntu-trusty-64:/vagrant/mod$ nm --undefined-only a.out
                 U abort
                 U ceil
                 U ceilf
                 U exp
                 U exp2
                 U exp2f
                 U expf
                 U fflush
                 U floor
                 U floorf
                 U fma
                 U fmaf
                 U fmax
                 U fmaxf
                 U fmaxl
                 U fmod
                 U fmodf
                 U fprintf
                 U _GLOBAL_OFFSET_TABLE_
                 U log
                 U log10
                 U log10f
                 U log2
                 U log2f
                 U logb
                 U logbf
                 U logbl
                 U logf
                 U memcmp
                 U memcpy
                 U pow
                 U powf
                 U round
                 U roundf
                 U scalbn
                 U scalbnf
                 U scalbnl
                 U _start
                 U stderr
                 U trunc
                 U truncf
                 U _Unwind_GetIP
                 U _Unwind_GetLanguageSpecificData
                 U _Unwind_GetRegionStart
                 U _Unwind_SetGR
                 U _Unwind_SetIP