patch 8.2.3967: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more errors to errors.h.
diff --git a/src/feature.h b/src/feature.h
index fa79d7a..fcd0d4b 100644
--- a/src/feature.h
+++ b/src/feature.h
@@ -1258,3 +1258,15 @@
 #if (!defined(FEAT_GUI) || defined(VIMDLL)) && defined(MSWIN)
 # define FEAT_VTP
 #endif
+
+#if defined(DYNAMIC_PERL) \
+	|| defined(DYNAMIC_PYTHON) || defined(DYNAMIC_PYTHON3) \
+	|| defined(DYNAMIC_RUBY) \
+	|| defined(DYNAMIC_TCL) \
+	|| defined(DYNAMIC_ICONV) \
+	|| defined(DYNAMIC_GETTEXT) \
+	|| defined(DYNAMIC_MZSCHEME) \
+	|| defined(DYNAMIC_LUA) \
+	|| defined(FEAT_TERMINAL)
+# define USING_LOAD_LIBRARY
+#endif