Avoid .eh_frame in ARM newlib.

Avoid .eh_frame in ARM newlib.

ARM newlib has various strcmp implementations that use .cfi_*
directives to generate unwind information.

The effect of this is that the generated objects contain .eh_frame
sections.  However, ARM uses its own unwind info format, not
.eh_frame, which is generated by ARM-specific directives, not .cfi_*.
The .eh_frame sections are useless, but also not removed by strip and
may be loaded into memory at runtime.

This patch fixes this by using .cfi_sections .debug_frame (as in
glibc) so that the directives generate .debug_frame instead.
.debug_frame is useful for the debugger, can be removed by strip, and
is not loaded into memory at runtime.

	* libc/machine/arm/strcmp-arm-tiny.S: Use .cfi_sections
	.debug_frame.
	* libc/machine/arm/strcmp-armv4.S: Likewise.
	* libc/machine/arm/strcmp-armv4t.S: Likewise.
	* libc/machine/arm/strcmp-armv6.S: Likewise.
	* libc/machine/arm/strcmp-armv6m.S: Likewise.
	* libc/machine/arm/strcmp-armv7.S: Likewise.
	* libc/machine/arm/strcmp-armv7m.S: Likewise.