kdc: annotate libkdc Windows function annotations

Annotate libkdc APIs with KDC_LIB_{CALL,FUNCTION} to ensure correct calling
convention and optimized DLL importing on Windows.

Ensure Windows and libtool export tables are consistent.

kdc/kdc.h

@@ -46,6 +46,16 @@
 #include <kx509_asn1.h>
 #include <gssapi/gssapi.h>
 
+#if !defined(BUILD_KDC_LIB) && defined(_WIN32)
+# define KDC_LIB_FUNCTION __declspec(dllimport)
+# define KDC_LIB_CALL     __stdcall
+# define KDC_LIB_VARIABLE __declspec(dllimport)
+#else
+# define KDC_LIB_FUNCTION
+# define KDC_LIB_CALL
+# define KDC_LIB_VARIABLE
+#endif
+
 #define heim_pcontext krb5_context
 #define heim_pconfig krb5_kdc_configuration *
 #include <heimbase-svc.h>