FindOpenSSL: Report crypto and ssl libraries separately

Some applications only need the OpenSSL crypto library and want to avoid
linking against the SSL library.  Set OPENSSL_CRYPTO_LIBRARY and
OPENSSL_SSL_LIBRARY in the code paths that do not need to find them
separately, and document them publicly.  This allows applications to be
more specific when linking against OpenSSL.

Help/release/dev/FindOpenSSL-separate-libs.rst

@@ -0,0 +1,7 @@
+FindOpenSSL-separate-libs
+-------------------------
+
+* The :module:`FindOpenSSL` module now reports ``crypto`` and ``ssl``
+  libraries separately in ``OPENSSL_CRYPTO_LIBRARY`` and
+  ``OPENSSL_SSL_LIBRARY``, respectively, to allow applications to
+  link to one without the other.

Modules/FindOpenSSL.cmake

@@ -16,10 +16,12 @@
 #
 # ::
 #
-#   OPENSSL_FOUND - system has the OpenSSL library
-#   OPENSSL_INCLUDE_DIR - the OpenSSL include directory
-#   OPENSSL_LIBRARIES - The libraries needed to use OpenSSL
-#   OPENSSL_VERSION - This is set to $major.$minor.$revision$path (eg. 0.9.8s)
+#   OPENSSL_FOUND - System has the OpenSSL library
+#   OPENSSL_INCLUDE_DIR - The OpenSSL include directory
+#   OPENSSL_CRYPTO_LIBRARY - The OpenSSL crypto library
+#   OPENSSL_SSL_LIBRARY - The OpenSSL SSL library
+#   OPENSSL_LIBRARIES - All OpenSSL libraries
+#   OPENSSL_VERSION - This is set to $major.$minor.$revision$patch (eg. 0.9.8s)
 
 #=============================================================================
 # Copyright 2006-2009 Kitware, Inc.
@@ -153,6 +155,8 @@ if(WIN32 AND NOT CYGWIN)
 
     mark_as_advanced(LIB_EAY_LIBRARY_DEBUG LIB_EAY_LIBRARY_RELEASE
                      SSL_EAY_LIBRARY_DEBUG SSL_EAY_LIBRARY_RELEASE)
+    set( OPENSSL_SSL_LIBRARY ${SSL_EAY_LIBRARY} )
+    set( OPENSSL_CRYPTO_LIBRARY ${LIB_EAY_LIBRARY} )
     set( OPENSSL_LIBRARIES ${SSL_EAY_LIBRARY} ${LIB_EAY_LIBRARY} )
   elseif(MINGW)
     # same player, for MinGW
@@ -181,6 +185,8 @@ if(WIN32 AND NOT CYGWIN)
     )
 
     mark_as_advanced(SSL_EAY LIB_EAY)
+    set( OPENSSL_SSL_LIBRARY ${SSL_EAY} )
+    set( OPENSSL_CRYPTO_LIBRARY ${LIB_EAY} )
     set( OPENSSL_LIBRARIES ${SSL_EAY} ${LIB_EAY} )
     unset(LIB_EAY_NAMES)
     unset(SSL_EAY_NAMES)
@@ -207,6 +213,8 @@ if(WIN32 AND NOT CYGWIN)
     )
 
     mark_as_advanced(SSL_EAY LIB_EAY)
+    set( OPENSSL_SSL_LIBRARY ${SSL_EAY} )
+    set( OPENSSL_CRYPTO_LIBRARY ${LIB_EAY} )
     set( OPENSSL_LIBRARIES ${SSL_EAY} ${LIB_EAY} )
   endif()
 else()