i tried to upx --best to your released pre-compiled linux binary, then run jsonpp and error occurred:

Segmentation fault (core dumped)

but i go build -ldflags="-s -w" jsonpp myself and then upx --best, everything is ok

go version: go1.8 linux/amd64
os:

lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.2 LTS
Release: 16.04
Codename: xenial

upx version:

upx --version
upx 3.91
UCL data compression library 1.03
LZMA SDK version 9.22 beta
Copyright (C) 1996-2013 Markus Franz Xaver Johannes Oberhumer
Copyright (C) 1996-2013 Laszlo Molnar
Copyright (C) 2000-2013 John F. Reiser
Copyright (C) 2002-2013 Jens Medoch
Copyright (C) 1999-2006 Igor Pavlov
UPX comes with ABSOLUTELY NO WARRANTY; for details type 'upx -L'.