libbacktrace: backport from mainline.

libbacktrace: backport from mainline.

* btest.c (test5): Replace #ifdef guard with 'unused' attribute
to fix compile warning when BACKTRACE_SUPPORTED isn't defined.
* dwarf.c (free_line_header): Don't free dirs if dirs_count == 0.
(read_line_header): Don't allocate dirs if dirs_count == 0.
* edtest.c: New file.
* edtest2.c: New file.
* Makefile.am (edtest_SOURCES, edtest_LDADD): Define.
(check_PROGRAMS): Add edtest.
(edtest2_build.c, gen_edtest2_build): New targets.
* Makefile.in: Rebuild.
* elf.c (backtrace_initialize): Always set *fileline_fn.
* ttest.c: New file.
* btest.c: Move support functions into testlib.c.  Change calls to
check to pass file name.
* testlib.c: New file, copied from (part of) btest.c.
* testlib.h: New file, declarations for testlib.c.
* edtest.c: Use testlib.h and testlib.c.
* configure.ac: Test for -pthread, set HAVE_PTHREAD conditional.
* Makefile.am (btest_SOURCES): Add testlib.c.
(edtest_SOURCES): Likewise.
(CHECK_PROGRAMS): Add ttest if HAVE_PTHREAD.
(ttest_SOURCES, ttest_CFLAGS, ttest_LDADD): Define.
* configure, Makefile.in: Rebuild.
* configure.ac: Add AC_SYS_LARGEFILE.
* config.h.in: Regenerate.
* configure: Likewise.
* filetype.awk: Add AIX XCOFF type detection.
* configure.ac: Recognize xcoff format.
* Makefile.am (FORMAT_FILES): Add xcoff.c.
* fileline.c: Include <unistd.h>.
(fileline_initialize): Add case for AIX procfs.
* xcoff.c: New file.
* configure, Makefile.in: Rebuild.
* configure.ac: Check for XCOFF32/XCOFF64.  Check for loadquery.
* filetype.awk: Separate AIX XCOFF32 and XCOFF64.
* xcoff.c: Add support for AIX XCOFF32 and XCOFF64 formats.
* configure, config.h.in: Regenerate.
* fileline.c (fileline_initialize): Print pid_t as long.
* xcoff.c: Don't leak a file descriptor if an archive is malformed.
* xcoff.c (xcoff_process_linenos): Initialize incl to NULL.
* libbacktrace/Makefile.in
(HAVE_PTHREAD_TRUE@@NATIVE_TRUE@ttest_CFLAGS): Add $(AM_CFLAGS)
* Makefile.am (ttest_CFLAGS): Add $(AM_CFLAGS)
* Makefile.in: Regenerate.

Change-Id: Ib61ad222b79b9c3a38d35705608f74041acc767a