Major Description
Since recent changes to squeasel landed in 8993716d7, the thirdparty build of squeasel has been broken on macOS 10.12. The OpenSSL system headers in /usr/include/openssl are not present in 10.12, and squeasel now depends on them. The error:
<..>/kudu/thirdparty/src/squeasel-c304d3f3481b07bf153979155f02e0aab24d01de/squeasel.c:153:10: fatal error: 'openssl/ssl.h' file not found
An relatively easy workaround is to install OpenSSL via homebrew and set the environment variable EXTRA_CFLAGS="-I/usr/local/opt/openssl/include" when building thirdparty.
We should come up with a long-term solution. tlipcon suggested that we might try to use pkg-config.