The problems encountered before have been eliminated. After upgrading to os x 10.11, /usr/include is no longer there. Because Apple has officially removed this directory, openssl/ssl.h file not found will appear during compilation.
After installing it through xcode-select install yesterday, the /usr/include directory appeared, but there was another problem with compilation:
./git-compat-util.h:270:10: fatal error: 'openssl/ssl.h' file not found
How to solve it?
The openssh library is missing. If it has been installed, the path is not correct
Download a package of openssl library separately?