mdbx-cmake: #if/#endif instead of cmake-conditions for posix/windows sources.

Change-Id: Ic95bd3ba345160cf1d68c79f11d6560d4c41cb2b

src/elements/lck-posix.c

@@ -12,6 +12,8 @@
  * <http://www.OpenLDAP.org/license.html>.
  */
 
+#if !(defined(_WIN32) || defined(_WIN64)) /* !Windows LCK-implementation */
+
 #include "internals.h"
 #include <sys/sem.h>
 
@@ -803,3 +805,10 @@ void mdbx_txn_unlock(MDBX_env *env) {
     mdbx_panic("%s() failed: err %d\n", __func__, rc);
   mdbx_jitter4testing(true);
 }
+
+#else
+#ifdef _MSC_VER
+#pragma warning(disable : 4206) /* nonstandard extension used: translation     \
+                                   unit is empty */
+#endif                          /* _MSC_VER (warnings) */
+#endif                          /* !Windows LCK-implementation */

src/elements/lck-windows.c

@@ -12,17 +12,15 @@
  * <http://www.OpenLDAP.org/license.html>.
  */
 
-#include "internals.h"
+#if defined(_WIN32) || defined(_WIN64) /* Windows LCK-implementation */
 
 /* PREAMBLE FOR WINDOWS:
  *
  * We are not concerned for performance here.
  * If you are running Windows a performance could NOT be the goal.
- * Otherwise please use Linux.
- *
- * Regards,
- * LY
- */
+ * Otherwise please use Linux. */
+
+#include "internals.h"
 
 static void mdbx_winnt_import(void);
 
@@ -799,3 +797,5 @@ static void mdbx_winnt_import(void) {
     mdbx_srwlock_ReleaseExclusive = stub_srwlock_ReleaseExclusive;
   }
 }
+
+#endif /* Windows LCK-implementation */