libbacktrace: test linker support for DWARF 5

On AIX, the compiler supports DWARF 5 but the linker does not.

2020-07-07 Clement Chigot <[email protected]>

	* configure.ac: Test linker support for DWARF5
	* configure: Regenerate

Author: ianlancetaylor

configure

@@ -12678,13 +12678,21 @@ CFLAGS="$CFLAGS -gdwarf-5"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int i;
+int
+main ()
+{
+return 0;
+  ;
+  return 0;
+}
 _ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_c_try_link "$LINENO"; then :
   libbacktrace_cv_lib_dwarf5=yes
 else
   libbacktrace_cv_lib_dwarf5=no
 fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
 CFLAGS=$CFLAGS_hold
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $libbacktrace_cv_lib_dwarf5" >&5

configure.ac

@@ -461,12 +461,12 @@ AC_SUBST(PTHREAD_CFLAGS)
 
 AM_CONDITIONAL(HAVE_PTHREAD, test "$libgo_cv_lib_pthread" = yes)
 
-dnl Test whether the compiler supports the -gdwarf-5 option.
+dnl Test whether the compiler and the linker support the -gdwarf-5 option.
 AC_CACHE_CHECK([whether -gdwarf-5 is supported],
 [libbacktrace_cv_lib_dwarf5],
 [CFLAGS_hold=$CFLAGS
 CFLAGS="$CFLAGS -gdwarf-5"
-AC_COMPILE_IFELSE([AC_LANG_SOURCE([int i;])],
+AC_LINK_IFELSE([AC_LANG_PROGRAM([int i;], [return 0;])],
 [libbacktrace_cv_lib_dwarf5=yes],
 [libbacktrace_cv_lib_dwarf5=no])
 CFLAGS=$CFLAGS_hold])