When a server is compiled with -fPIE, my_addr_resolve needs to
subtract the info.dli_fbase from symbol addresses in memory for
addr2line to recognize them.  When a server is compiled without -fPIE,
my_addr_resolve should not do it.  Unfortunately not all compilers
define __PIE__ when -fPIE was used (e.g. older gcc doesn't), so we
have to resort to run-time detection.