Break out OpenSSL-specific code to separate files.

This refactoring is in preparation for adding support for other SSL
implementations, with no user-visible effects. There are now two #defines,
USE_OPENSSL which is defined when building with OpenSSL, and USE_SSL which
is defined when building with any SSL implementation. Currently, OpenSSL is
the only implementation so the two #defines go together, but USE_SSL is
supposed to be used for implementation-independent code.

The libpq SSL code is changed to use a custom BIO, which does all the raw
I/O, like we've been doing in the backend for a long time. That makes it
possible to use MSG_NOSIGNAL to block SIGPIPE when using SSL, which avoids
a couple of syscall for each send(). Probably doesn't make much performance
difference in practice - the SSL encryption is expensive enough to mask the
effect - but it was a natural result of this refactoring.

Based on a patch by Martijn van Oosterhout from 2006. Briefly reviewed by
Alvaro Herrera, Andreas Karlsson, Jeff Janes.

1 files changed, 1 insertions, 1 deletions

diff --git a/configure b/configure
index 0b0a6566f36..0f435b5c946 100755
--- a/configure
+++ b/configure
@@ -5492,7 +5492,7 @@ if test "${with_openssl+set}" = set; then :
   case $withval in
     yes)
 
-$as_echo "#define USE_SSL 1" >>confdefs.h
+$as_echo "#define USE_OPENSSL 1" >>confdefs.h
 
       ;;
     no)