Revert "fixes #717 NN_STATIC_LIB not properly handled on WIN32"

This reverts commit 722f87913395b84b193c0f39f9a2d68422a7264d.

(Not fully baked, needs work.)
diff --git a/CMakeLists.txt b/CMakeLists.txt
index bb91a51..f9e642a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -157,14 +157,6 @@
     set(NN_REQUIRED_LIBRARIES ${NN_REQUIRED_LIBRARIES} ws2_32)
     set(NN_REQUIRED_LIBRARIES ${NN_REQUIRED_LIBRARIES} mswsock)
     set(NN_REQUIRED_LIBRARIES ${NN_REQUIRED_LIBRARIES} advapi32)
-
-    # Ensure tests/tools built as EXE choose symbol visibility appropriate for
-    # linking the library, whether static or dynamic.
-    if (NN_STATIC_LIB)
-        add_definitions (-DNN_WIN32_LIB_LINK)
-    else ()
-        add_definitions (-DNN_WIN32_DLL_LINK)
-    endif ()
 else ()
     # Unconditionally declare the following feature test macros.  These are
     # needed for some platforms (glibc and SunOS/illumos) and should be harmless
diff --git a/src/nn.h b/src/nn.h
index 7f0bbb8..067bea3 100644
--- a/src/nn.h
+++ b/src/nn.h
@@ -36,14 +36,10 @@
 
 /*  Handle DSO symbol visibility. */
 #if !defined(NN_EXPORT)
-#    if defined(_WIN32)
-#        if defined(NN_STATIC_LIB)
-#            define NN_EXPORT
-#        elif defined(NN_WIN32_LIB_LINK)
-#            define NN_EXPORT
-#        elif defined(NN_SHARED_LIB)
+#    if defined(_WIN32) && !defined(NN_STATIC_LIB)
+#        if defined NN_SHARED_LIB
 #            define NN_EXPORT __declspec(dllexport)
-#        else defined(NN_WIN32_DLL_LINK)
+#        else
 #            define NN_EXPORT __declspec(dllimport)
 #        endif
 #    else