diff --git a/Makefile-rpm-ostree.am b/Makefile-rpm-ostree.am
index 613dfd68..e96c3863 100644
--- a/Makefile-rpm-ostree.am
+++ b/Makefile-rpm-ostree.am
@@ -46,7 +46,7 @@ rpm_ostree_SOURCES = src/app/main.cxx \
 	src/app/rpmostree-builtin-finalize-deployment.cxx \
 	src/app/rpmostree-db-builtin-diff.cxx \
 	src/app/rpmostree-db-builtin-list.cxx \
-	src/app/rpmostree-db-builtin-version.c \
+	src/app/rpmostree-db-builtin-version.cxx \
 	src/app/rpmostree-dbus-helpers.cxx \
 	src/app/rpmostree-dbus-helpers.h \
 	src/app/rpmostree-override-builtins.h \
diff --git a/src/app/rpmostree-db-builtin-version.c b/src/app/rpmostree-db-builtin-version.cxx
similarity index 97%
rename from src/app/rpmostree-db-builtin-version.c
rename to src/app/rpmostree-db-builtin-version.cxx
index d5ca0c62..f25899e8 100644
--- a/src/app/rpmostree-db-builtin-version.c
+++ b/src/app/rpmostree-db-builtin-version.cxx
@@ -34,7 +34,7 @@ _builtin_db_version (OstreeRepo *repo, GPtrArray *revs,
 {
   for (guint num = 0; num < revs->len; num++)
     {
-      const char *rev = revs->pdata[num];
+      auto rev = static_cast<const char *>(revs->pdata[num]);
 
       g_autoptr(RpmRevisionData) rpmrev = rpmrev_new (repo, rev, NULL, cancellable, error);
       if (!rpmrev)