Update X86 Bionic CRT files for unwind/exceptions

Several updates to Bionic crt*.o files to implement Linux/x86
stack unwind/exception handling.
Mark __dso_handle as hidden.
Note: Requires complete rebuild due to CRT changes. Google will
need to regenerate and check-in all the prebuilt x86 CRT object
files and libraries which link to them.

Change-Id: I191ce1afb0dee7bbc28dcd9694e5919226dbd070
Signed-off-by: Bruce J Beare <bruce.j.beare@intel.com>
Signed-off-by: Mark D Horn <mark.d.horn@intel.com>
Author: Lu, Hongjiu <hongjiu.lu@intel.com>
diff --git a/libc/private/__dso_handle.S b/libc/private/__dso_handle.S
index fcebab6..a6395dd6 100644
--- a/libc/private/__dso_handle.S
+++ b/libc/private/__dso_handle.S
@@ -32,6 +32,7 @@
 #
         .section .bss
         .align 4
+	.hidden __dso_handle
         .globl __dso_handle
 __dso_handle:
         .long 0