[ARM] Adding strlen.S

The patch adds strlen.S to contain the complementary preprocessor
logic to strlen-stub.c intended to provide #inclusion of alternative
.S implementations.

Initially we just include the existing strlen-armv7.S implementation.

We rewrite _ISA_ARMV7 in both strlen.S and strlen-stub.c to use the
underlying existing underlying defintion from arm_asm.h in order to
avoide including that file, this is in effect the first step towards a
move to ACLE predefines only.

Tested by building newlib and comparing libc.a binaries before and
after for all permutations of:

      Architectures:
        armv4 armv4t armv5 armv5t armv5te armv6 armv6j armv6k
        armv6z armv6kz armv6t2 armv6-m armv6s-m armv7 armv7-a
        armv7ve armv7-r armv7-m armv7e-m armv8-a iwmmxt iwmmxt2

      ISAs:
        thumb arm

      Optimization Levels:
        Os O2

      Excluding:
        armv6s-m -mthumb
        armv6-m -mthumb

        armv6zk -mthumb
        armv6z -mthumb
        armv6k -mthumb
        armv6j -mthumb

1 files changed, 8 insertions, 0 deletions

diff --git a/newlib/ChangeLog b/newlib/ChangeLog
index 7c2f38aa3..44dfdcdce 100644
--- a/newlib/ChangeLog
+++ b/newlib/ChangeLog
@@ -1,5 +1,13 @@
 2015-11-13  Marcus Shawcroft  <marcus.shawcroft@arm.com>
 
+	* libc/machine/arm/Makefile.am: Adding strlen.S.
+	* libc/machine/arm/Makefile.in: Regenerate.
+	* libc/machine/arm/strlen.S: New.
+	* libc/machine/arm/strlen-stub.c: Rewrite #if condition.
+	* libc/machine/arm/strlen-armv7.S: Remove surrounding #if.
+
+2015-11-13  Marcus Shawcroft  <marcus.shawcroft@arm.com>
+
 	* libc/machine/arm/Makefile.am: Rename strlen.c to strlen-stub.c
 	* libc/machine/arm/Makefile.in: Regenerate.
 	* libc/machine/arm/strlen.c: Rename to...