PORT: Add OPENSSL_Applink() to ssl4pl.dll

This function is used by OpenSSL to get module-consistent of the MS
CRT library.  It is expected at the application level.   This patch
tries to keep it locally in the ssl binding with a small relay function
from the SWI-Prolog executable.

CMakeLists.txt

@@ -62,7 +62,7 @@ AC_CHECK_HEADERS(openssl/kdf.h)
 AC_CHECK_HEADERS(openssl/core_names.h)
 AC_CHECK_HEADERS(openssl/param_build.h)
 AC_CHECK_HEADERS(openssl/applink.c)
-if(HAVE_OPENSSL_APPLINK_C)
+if(MSVC AND HAVE_OPENSSL_APPLINK_C)
   set(APPLINK ssl_applink.c)
 else()
   set(APPLINK)
@@ -200,7 +200,7 @@ add_compile_options(-D__SWI_PROLOG__
 
 swipl_plugin(
     ssl4pl
-    C_SOURCES ssl4pl.c ../clib/error.c
+    C_SOURCES ssl4pl.c ${APPLINK} ../clib/error.c
     THREADED
     C_LIBS ${OPENSSL_SSL_LIBRARY} ${OPENSSL_CRYPTO_LIBRARY} ${OPENSSL_OS_LIBS}
     C_INCLUDE_DIR ${OPENSSL_INCLUDE_DIR}

ssl_applink.c

@@ -0,0 +1,40 @@
+/*  Part of SWI-Prolog
+
+    Author:        Jan Wielemaker
+    E-mail:        jan@swi-prolog.org
+    WWW:           http://www.swi-prolog.org
+    Copyright (c)  2023, SWI-Prolog Solutions b.v.
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in
+       the documentation and/or other materials provided with the
+       distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+    POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#define _CRT_SECURE_NO_WARNINGS 1
+#include <config.h>
+
+#ifdef HAVE_OPENSSL_APPLINK_C
+#include <openssl/applink.c>
+#endif /*HAVE_OPENSSL_APPLINK_C*/