diff --git a/libc/arch-arm/arm.mk b/libc/arch-arm/arm.mk
index 55f9978..89a1ce0 100644
--- a/libc/arch-arm/arm.mk
+++ b/libc/arch-arm/arm.mk
@@ -10,19 +10,13 @@
     bionic/mmap.cpp
 
 libc_common_src_files_arm += \
+    bionic/index.cpp \
     bionic/memchr.c \
     bionic/memmove.c.arm \
     bionic/memrchr.c \
     bionic/strchr.cpp \
     bionic/strnlen.c \
-    string/bcopy.c \
-    string/index.c \
-    string/strlcat.c \
-    string/strlcpy.c \
-    string/strncat.c \
-    string/strncmp.c \
-    string/strncpy.c \
-    string/strrchr.c \
+    bionic/strrchr.cpp \
     upstream-freebsd/lib/libc/string/wcscat.c \
     upstream-freebsd/lib/libc/string/wcschr.c \
     upstream-freebsd/lib/libc/string/wcscmp.c \
@@ -30,6 +24,12 @@
     upstream-freebsd/lib/libc/string/wcslen.c \
     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/strlcat.c \
+    upstream-openbsd/lib/libc/string/strlcpy.c \
+    upstream-openbsd/lib/libc/string/strncat.c \
+    upstream-openbsd/lib/libc/string/strncmp.c \
+    upstream-openbsd/lib/libc/string/strncpy.c \
 
 # The C++ fortify function implementations for which there is an
 # arm assembler version.
diff --git a/libc/arch-arm/generic/generic.mk b/libc/arch-arm/generic/generic.mk
index 063d893..2bc84e0 100644
--- a/libc/arch-arm/generic/generic.mk
+++ b/libc/arch-arm/generic/generic.mk
@@ -1,9 +1,9 @@
 libc_bionic_src_files_arm += \
     arch-arm/generic/bionic/memcpy.S \
     arch-arm/generic/bionic/memset.S \
-    string/strcat.c \
     arch-arm/generic/bionic/strcmp.S \
     arch-arm/generic/bionic/strcpy.S \
     arch-arm/generic/bionic/strlen.c \
     bionic/__strcat_chk.cpp \
     bionic/__strcpy_chk.cpp \
+    upstream-openbsd/lib/libc/string/strcat.c \