diff --git a/src/vernum.c b/src/vernum.c
index 9b19149c..c72da35f 100644
--- a/src/vernum.c
+++ b/src/vernum.c
@@ -8,6 +8,6 @@
 
 #include "vernum.h"
 
-char *build_date = __DATE__;
-char *build_time = __TIME__;
-char *build_id = BUILD_ID;
+const char *build_date = __DATE__;
+const char *build_time = __TIME__;
+const char *build_id = BUILD_ID;
diff --git a/src/vernum.h b/src/vernum.h
index 098bc34a..127abb7d 100644
--- a/src/vernum.h
+++ b/src/vernum.h
@@ -2,6 +2,8 @@
 #ifndef EL__VERNUM_H
 #define EL__VERNUM_H
 
-extern char *build_date, *build_time, *build_id;
+extern const char *build_date;
+extern const char *build_time;
+extern const char *build_id;
 
 #endif /* EL__VERNUM_H */