MD5 don't know the problem (Solved)

pdf_writer.c:(.text+0x42e): undefined reference to `MD5'

ref:
https://packages.ubuntu.com/xenial/amd64/libssl-dev/filelist

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=802235

solution

把-lcrypto放到cc的最后。