Fix mips build.

Move various mips-only things into the arch-mips directory. As soon as mips
writes assembler replacements, we can remove these.

Change-Id: Ia7308559bc361f5c8df3e1d456b381865e060b93
diff --git a/libc/arch-mips64/mips64.mk b/libc/arch-mips64/mips64.mk
index 26733cb..7990c69 100644
--- a/libc/arch-mips64/mips64.mk
+++ b/libc/arch-mips64/mips64.mk
@@ -10,12 +10,14 @@
     bionic/__strcpy_chk.cpp \
     bionic/__strcat_chk.cpp \
     bionic/memchr.c \
-    bionic/memcmp.c \
     bionic/memrchr.c \
-    bionic/memset.c \
     bionic/strchr.cpp \
     bionic/strnlen.c \
     bionic/strrchr.cpp \
+    arch-mips/string/memcmp.c \
+    arch-mips/string/memcpy.c \
+    arch-mips/string/memset.c \
+    arch-mips/string/strlen.c \
 
 libc_freebsd_src_files_mips64 += \
     upstream-freebsd/lib/libc/string/wcscat.c \
@@ -28,7 +30,6 @@
     upstream-freebsd/lib/libc/string/wmemmove.c \
 
 libc_openbsd_src_files_mips64 += \
-    upstream-openbsd/lib/libc/string/memcpy.c \
     upstream-openbsd/lib/libc/string/memmove.c \
     upstream-openbsd/lib/libc/string/stpcpy.c \
     upstream-openbsd/lib/libc/string/stpncpy.c \
@@ -37,7 +38,6 @@
     upstream-openbsd/lib/libc/string/strcpy.c \
     upstream-openbsd/lib/libc/string/strlcat.c \
     upstream-openbsd/lib/libc/string/strlcpy.c \
-    upstream-openbsd/lib/libc/string/strlen.c \
     upstream-openbsd/lib/libc/string/strncat.c \
     upstream-openbsd/lib/libc/string/strncmp.c \
     upstream-openbsd/lib/libc/string/strncpy.c \