diff --git a/Makefile-rpm-ostree.am b/Makefile-rpm-ostree.am
index 1caa48ed..1e46317a 100644
--- a/Makefile-rpm-ostree.am
+++ b/Makefile-rpm-ostree.am
@@ -30,7 +30,7 @@ rpm_ostree_SOURCES = src/app/main.cxx \
 	src/app/rpmostree-builtin-cliwrap.cxx \
 	src/app/rpmostree-builtin-cleanup.cxx \
 	src/app/rpmostree-builtin-initramfs.cxx \
-	src/app/rpmostree-builtin-initramfs-etc.c \
+	src/app/rpmostree-builtin-initramfs-etc.cxx \
 	src/app/rpmostree-builtin-livefs.cxx \
 	src/app/rpmostree-builtin-usroverlay.cxx \
 	src/app/rpmostree-builtin-override.cxx \
diff --git a/src/app/rpmostree-builtin-initramfs-etc.c b/src/app/rpmostree-builtin-initramfs-etc.cxx
similarity index 100%
rename from src/app/rpmostree-builtin-initramfs-etc.c
rename to src/app/rpmostree-builtin-initramfs-etc.cxx