diff --git a/contrib/51d/src/pattern/51Degrees.h b/contrib/51d/src/pattern/51Degrees.h
index 6a646a69f..9aaf9498e 100644
--- a/contrib/51d/src/pattern/51Degrees.h
+++ b/contrib/51d/src/pattern/51Degrees.h
@@ -24,6 +24,10 @@
 #define FIFTYONEDEGREES_H_PATTERN_INCLUDED
 #endif
 
+#ifndef FIFTYONEDEGREES_DUMMY_LIB
+#define FIFTYONEDEGREES_DUMMY_LIB
+#endif
+
 #include <stdint.h>
 
 typedef enum e_fiftyoneDegrees_MatchMethod {
diff --git a/contrib/51d/src/trie/51Degrees.h b/contrib/51d/src/trie/51Degrees.h
index a5f0868c4..bedcfd7b3 100644
--- a/contrib/51d/src/trie/51Degrees.h
+++ b/contrib/51d/src/trie/51Degrees.h
@@ -24,6 +24,10 @@
 #define FIFTYONEDEGREES_H_TRIE_INCLUDED
 #endif
 
+#ifndef FIFTYONEDEGREES_DUMMY_LIB
+#define FIFTYONEDEGREES_DUMMY_LIB
+#endif
+
 #include <stdint.h>
 
 typedef enum e_fiftyoneDegrees_DataSetInitStatus {
diff --git a/src/51d.c b/src/51d.c
index bf4065802..344be41be 100644
--- a/src/51d.c
+++ b/src/51d.c
@@ -827,4 +827,17 @@ INITCALL1(STG_REGISTER, sample_register_convs, &conv_kws);
 
 REGISTER_POST_CHECK(init_51degrees);
 REGISTER_POST_DEINIT(deinit_51degrees);
-REGISTER_BUILD_OPTS("Built with 51Degrees support.");
+
+#if defined(FIFTYONEDEGREES_H_PATTERN_INCLUDED)
+#ifndef FIFTYONEDEGREES_DUMMY_LIB
+	REGISTER_BUILD_OPTS("Built with 51Degrees Pattern support.");
+#else
+	REGISTER_BUILD_OPTS("Built with 51Degrees Pattern support (dummy library).");
+#endif
+#elif defined(FIFTYONEDEGREES_H_TRIE_INCLUDED)
+#ifndef FIFTYONEDEGREES_DUMMY_LIB
+	REGISTER_BUILD_OPTS("Built with 51Degrees Trie support.");
+#else
+	REGISTER_BUILD_OPTS("Built with 51Degrees Trie support (dummy library).");
+#endif
+#endif
\ No newline at end of file