diff --git a/libc/arch-x86/x86.mk b/libc/arch-x86/x86.mk
index 3dc71d1..8aa2645 100644
--- a/libc/arch-x86/x86.mk
+++ b/libc/arch-x86/x86.mk
@@ -40,6 +40,9 @@
 include $(arch_variant_mk)
 libc_common_additional_dependencies += $(arch_variant_mk)
 
+libc_netbsd_src_files_x86 := \
+    upstream-netbsd/common/lib/libc/hash/sha1/sha1.c \
+
 arch_variant_mk :=
 
 libc_crt_target_cflags_x86 := \