unwinder: Add SFrame unwinder tests

unwinder: Add SFrame unwinder tests

[Changes in V4]
  - Addressed Mike's review comments.
    - Be careful with the use of # and dnl in configure.ac
    - Add AC_CANONICAL_TARGET as we check for target.
    - Remove the LC_ALL=C bits.
  - Minor code fixups in the testcases
    - Removed unnecessary unistd.h.
    - use ATTRIBUTE_NOCLONE consistently.
    - Other minor cleanups.
[End of changes in V4]

[Changes in V3]
  - Added two new tests with attributes -f(no-)omit-frame-pointer.
  - Minor adjustments due to buildsystem changes in libsframe.
[End of changes in V3]

[Changes in V2]
  - minor changes in filenames in the testsuite.
[End of changes in V2]

Add tests for backtracing using SFrame section.

ChangeLog:

	* libsframe/Makefile.in: Regenerated.
	* libsframe/configure: Regenerated.
	* libsframe/configure.ac: Check for cross compilation.
	* libsframe/testsuite/Makefile.in: Regenerated.
	* libsframe/testsuite/config/default.exp: Load
	  sframe-lib.exp.
	* libsframe/testsuite/libsframe.decode/Makefile.in:
	  Regenerated.
	* libsframe/testsuite/libsframe.encode/Makefile.in:
	  Regenerated.
	* libsframe/testsuite/lib/sframe-lib.exp: New file.  Add
	  procedures for handling unwinder tests.
	* libsframe/testsuite/libsframe.unwind/backtrace.c: New test.
	* libsframe/testsuite/libsframe.unwind/backtrace.lk: New test.
	* libsframe/testsuite/libsframe.unwind/inline-cmds.c: New test.
	* libsframe/testsuite/libsframe.unwind/inline-cmds.lk: New test.
	* libsframe/testsuite/libsframe.unwind/inline.c: New test.
	* libsframe/testsuite/libsframe.unwind/inline.lk: New test.
	* libsframe/testsuite/libsframe.unwind/solib-lib1.c: New test.
	* libsframe/testsuite/libsframe.unwind/solib-lib2.c: New test.
	* libsframe/testsuite/libsframe.unwind/solib-main.c: New test.
	* libsframe/testsuite/libsframe.unwind/solib-main.d: New test.
	* libsframe/testsuite/libsframe.unwind/solib.exp: New file.
	* libsframe/testsuite/libsframe.unwind/solib-lib1.h: New test.
	* libsframe/testsuite/libsframe.unwind/solib-lib2.h: New test.
	* libsframe/testsuite/libsframe.unwind/tailcall.c: New test.
	* libsframe/testsuite/libsframe.unwind/tailcall.lk: New test.
	* libsframe/testsuite/libsframe.unwind/ttest.c: New test.
	* libsframe/testsuite/libsframe.unwind/ttest.lk: New test.
	* libsframe/testsuite/libsframe.unwind/unwind.exp: New file.
	* libsframe/testsuite/libsframe.unwind/backtrace-fp-attr-1.c:
	  Likewise.
	* libsframe/testsuite/libsframe.unwind/backtrace-fp-attr-1.lk:
	  Likewise.
	* libsframe/testsuite/libsframe.unwind/backtrace-fp-attr-2.c:
	  Likewise.
	* libsframe/testsuite/libsframe.unwind/backtrace-fp-attr-2.lk:
	  Likewise.