Move the SSL BIO into ssl/ from decrepit/.

This is purely to support curl, which now has HTTPS proxy support that,
sadly, uses the BIO SSL. Don't use the BIO SSL for anything else.

Change-Id: I9ef6c9773ec87a11e0b5a93968386ac4b351986d
Reviewed-on: https://boringssl-review.googlesource.com/13600
Commit-Queue: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/decrepit/CMakeLists.txt b/decrepit/CMakeLists.txt
index ee49bc8..223320d 100644
--- a/decrepit/CMakeLists.txt
+++ b/decrepit/CMakeLists.txt
@@ -1,7 +1,6 @@
 include_directories(../include)
 
 add_subdirectory(bio)
-add_subdirectory(biossl)
 add_subdirectory(blowfish)
 add_subdirectory(cast)
 add_subdirectory(des)
@@ -20,7 +19,6 @@
   decrepit
 
   $<TARGET_OBJECTS:bio_decrepit>
-  $<TARGET_OBJECTS:biossl_decrepit>
   $<TARGET_OBJECTS:blowfish>
   $<TARGET_OBJECTS:cast>
   $<TARGET_OBJECTS:des_decrepit>
diff --git a/decrepit/biossl/CMakeLists.txt b/decrepit/biossl/CMakeLists.txt
deleted file mode 100644
index 39fe139..0000000
--- a/decrepit/biossl/CMakeLists.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-include_directories(../../include)
-
-add_library(
-  biossl_decrepit
-
-  OBJECT
-
-  bio_ssl.c
-)
diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index 326a82b..3bb5b78 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -3671,7 +3671,9 @@
 
 /* BIO_f_ssl returns a |BIO_METHOD| that can wrap an |SSL*| in a |BIO*|. Note
  * that this has quite different behaviour from the version in OpenSSL (notably
- * that it doesn't try to auto renegotiate). */
+ * that it doesn't try to auto renegotiate).
+ *
+ * IMPORTANT: if you are not curl, don't use this. */
 OPENSSL_EXPORT const BIO_METHOD *BIO_f_ssl(void);
 
 /* BIO_set_ssl sets |ssl| as the underlying connection for |bio|, which must
diff --git a/ssl/CMakeLists.txt b/ssl/CMakeLists.txt
index 7102769..afc3a39 100644
--- a/ssl/CMakeLists.txt
+++ b/ssl/CMakeLists.txt
@@ -3,6 +3,7 @@
 add_library(
   ssl
 
+  bio_ssl.c
   custom_extensions.c
   handshake_server.c
   handshake_client.c
diff --git a/decrepit/biossl/bio_ssl.c b/ssl/bio_ssl.c
similarity index 100%
rename from decrepit/biossl/bio_ssl.c
rename to ssl/bio_ssl.c