the banquise-to-bigpatch-17.patch which the 1.6.40 ebuild applies to johntheripper uses the function floor() which means that linking fails unless "-lm" is specified to the linker. I'll attach a patch to make 1.6.40-r1 which fixes this.
Created attachment 76876 [details, diff] Patch create jacktheripper-1.6.40-r1 which fixes linkage problem
added - thankyou.