libbacktrace: read symbol table of debuginfo file

These become another symbol table to search.  This is needed if people
use --strip-all rather than --strip-debug when adding a debuglink
section.

Patch is from GitHub user pickard1.

Fixes #113

	* elf.c (elf_add): Add the symbol table from a debuginfo file.
	* Makefile.am (MAKETESTS): Add buildidfull and gnudebuglinkfull
	variants of buildid and gnudebuglink tests.
	(%_gnudebuglinkfull, %_buildidfull): New patterns.
	* Makefile.in: Regenerate.

Makefile.am

@@ -258,7 +258,7 @@ b2test_LDFLAGS = -Wl,--build-id
 b2test_LDADD = libbacktrace_elf_for_test.la
 
 check_PROGRAMS += b2test
-MAKETESTS += b2test_buildid
+MAKETESTS += b2test_buildid b2test_buildidfull
 
 if HAVE_DWZ
 
@@ -268,7 +268,7 @@ b3test_LDFLAGS = -Wl,--build-id
 b3test_LDADD = libbacktrace_elf_for_test.la
 
 check_PROGRAMS += b3test
-MAKETESTS += b3test_dwz_buildid
+MAKETESTS += b3test_dwz_buildid b3test_dwz_buildidfull
 
 endif HAVE_DWZ
 
@@ -444,12 +444,16 @@ endif HAVE_PTHREAD
 
 if HAVE_OBJCOPY_DEBUGLINK
 
-MAKETESTS += btest_gnudebuglink
+MAKETESTS += btest_gnudebuglink btest_gnudebuglinkfull
 
 %_gnudebuglink: %
 	$(OBJCOPY) --only-keep-debug $< $@.debug
 	$(OBJCOPY) --strip-debug --add-gnu-debuglink=$@.debug $< $@
 
+%_gnudebuglinkfull: %
+	$(OBJCOPY) --only-keep-debug $< $@.debug
+	$(OBJCOPY) --strip-all --add-gnu-debuglink=$@.debug $< $@
+
 endif HAVE_OBJCOPY_DEBUGLINK
 
 %_buildid: %
@@ -458,6 +462,12 @@ endif HAVE_OBJCOPY_DEBUGLINK
 	  $<
 	$(OBJCOPY) --strip-debug $< $@
 
+%_buildidfull: %
+	./install-debuginfo-for-buildid.sh \
+	  "$(TEST_BUILD_ID_DIR)" \
+	  $<
+	$(OBJCOPY) --strip-all $< $@
+
 if HAVE_COMPRESSED_DEBUG
 
 ctestg_SOURCES = btest.c testlib.c