@rough-minister-58256:

build/temp.macosx-10.11-x86_64-2.7/_openssl.c:434:10: fatal error: 'openssl/opensslv.h' file not found
#include <openssl/opensslv.h>
         ^
1 error generated.
error: command 'clang' failed with exit status 1

during https://www.pantsbuild.org/release.html would indicate that this OSX box doesn't have openssl headers in the expected location?