diff --git a/libc/arch-x86_64/x86_64.mk b/libc/arch-x86_64/x86_64.mk
index 9bce065..f0010f3 100644
--- a/libc/arch-x86_64/x86_64.mk
+++ b/libc/arch-x86_64/x86_64.mk
@@ -19,6 +19,8 @@
     upstream-freebsd/lib/libc/string/wcsrchr.c \
     upstream-freebsd/lib/libc/string/wmemcmp.c \
     upstream-openbsd/lib/libc/string/bcopy.c \
+    upstream-openbsd/lib/libc/string/stpcpy.c \
+    upstream-openbsd/lib/libc/string/stpncpy.c \
     upstream-openbsd/lib/libc/string/strcat.c \
     upstream-openbsd/lib/libc/string/strcmp.c \
     upstream-openbsd/lib/libc/string/strcpy.c \