commit 0f9094a77700d92ad304150ed55b2fa9faaec981
author Sergey Kandaurov <pluknet@nginx.com> Thu Apr 04 16:26:56 2019 +0300
committer Sergey Kandaurov <pluknet@nginx.com> Thu Apr 04 16:26:56 2019 +0300
tree 40ee1517a846c557a1a4347f0905e8dddcc8e15a
parent 7c04dbbd99455482c4e4ed82a0ae3847e33be5df

Win32: preserving binary compatibility with Windows XP - Vista.

OpenSSL 1.1.0 and above uses BCrypt if available (Windows 7 or higher).
This results in an unusable binary on older Windows versions, when building
with newer Windows SDK (such as 7.0A).  Using CFLAGS to define _WIN32_WINNT
allows to set a desired ABI and make sure the binary works with Windows XP.

To not mix with other potential CFLAGS uses, it is set in GNUmakefile.