Switch a number of files to C++.

http://i1.kym-cdn.com/photos/images/original/000/242/631/382.gif

In the first step, switch C files to C++ individually, keeping
everything in internal.h C-compatible. We'll make minimal changes needed
to get things compiling (notably a lot of goto errs will need to turn to
bssl::UniquePtr right away), but more aggressive changes will happen in
later steps.

(To avoid a rebase, I'm intentionally avoiding files that would conflict
with CLs in flight right now.)

Bug: 132
Change-Id: Id4cfd722e7b57d1df11f27236b4658b5d39b5fd2
Reviewed-on: https://boringssl-review.googlesource.com/17667
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/ssl/CMakeLists.txt b/ssl/CMakeLists.txt
index 0c09443..94a1741 100644
--- a/ssl/CMakeLists.txt
+++ b/ssl/CMakeLists.txt
@@ -3,21 +3,21 @@
 add_library(
   ssl
 
-  bio_ssl.c
-  custom_extensions.c
-  d1_both.c
-  d1_lib.c
-  d1_pkt.c
-  d1_srtp.c
-  dtls_method.c
-  dtls_record.c
+  bio_ssl.cc
+  custom_extensions.cc
+  d1_both.cc
+  d1_lib.cc
+  d1_pkt.cc
+  d1_srtp.cc
+  dtls_method.cc
+  dtls_record.cc
   handshake_client.c
   handshake_server.c
-  s3_both.c
-  s3_lib.c
-  s3_pkt.c
+  s3_both.cc
+  s3_lib.cc
+  s3_pkt.cc
   ssl_aead_ctx.c
-  ssl_asn1.c
+  ssl_asn1.cc
   ssl_buffer.c
   ssl_cert.c
   ssl_cipher.c
@@ -30,7 +30,7 @@
   ssl_stat.c
   ssl_transcript.c
   ssl_versions.c
-  ssl_x509.c
+  ssl_x509.cc
   t1_enc.c
   t1_lib.c
   tls_method.c