Break bionic implementations into arch versions.

Move arch specific code for arm, mips, x86 into separate
makefiles.
In addition, add different arm cpu versions of memcpy/memset.

Bug: 8005082

Merge from internal master (acdde8c1cf8e8beed98c052757d96695b820b50c).

Change-Id: I04f3d0715104fab618e1abf7cf8f7eec9bec79df
diff --git a/libc/arch-x86/x86.mk b/libc/arch-x86/x86.mk
new file mode 100644
index 0000000..0e5d283
--- /dev/null
+++ b/libc/arch-x86/x86.mk
@@ -0,0 +1,27 @@
+_LIBC_ARCH_COMMON_SRC_FILES := \
+    arch-x86/bionic/clone.S \
+    arch-x86/bionic/_exit_with_stack_teardown.S \
+    arch-x86/bionic/futex_x86.S \
+    arch-x86/bionic/__get_sp.S \
+    arch-x86/bionic/__get_tls.c \
+    arch-x86/bionic/_setjmp.S \
+    arch-x86/bionic/setjmp.S \
+    arch-x86/bionic/__set_tls.c \
+    arch-x86/bionic/sigsetjmp.S \
+    arch-x86/bionic/syscall.S \
+    arch-x86/bionic/vfork.S \
+    arch-x86/string/bcopy_wrapper.S \
+    arch-x86/string/bzero_wrapper.S \
+    arch-x86/string/ffs.S \
+    arch-x86/string/memcmp_wrapper.S \
+    arch-x86/string/memcpy_wrapper.S \
+    arch-x86/string/memmove_wrapper.S \
+    arch-x86/string/memset_wrapper.S \
+    arch-x86/string/strcmp_wrapper.S \
+    arch-x86/string/strlen_wrapper.S \
+    arch-x86/string/strncmp_wrapper.S \
+
+_LIBC_ARCH_STATIC_SRC_FILES := \
+    bionic/dl_iterate_phdr_static.c \
+
+_LIBC_ARCH_DYNAMIC_SRC_FILES :=