Putting @ ahead of command (like @echo) is only valid when it is single
line Makefile recipe. If it is inside of shell script (of Makefile recipe),
we will get '@echo not found'. Sorry, it's long been a problem. Now fixed.
Add the line
+_GIT_ENV+= GIT_SSL_NO_VERIFY=true
for "SSL certificate problem: unable to get local issuer certificate"