configure: Fix test for libunwind

Most functions in libunwind.h are actually mapped via macros to obscure
function names, so checking for these would require some elaborate test
via AC_LINK_IFELSE().  However, unw_backtrace() seems to be one of the few
actual functions so lets use this for now, even though we don't call it
ourselves later.

Fixes: 016228c15843 ("configure: Check for actual functions in libraries
with AC_CHECK_LIB")

diff --git a/configure.ac b/configure.ac
index 5453e5b..89d885c 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -1222,7 +1222,7 @@ if test x$bfd_backtraces = xtrue; then
 fi
 
 if test x$unwind_backtraces = xtrue; then
-       AC_CHECK_LIB([unwind],[unw_getcontext],[LIBS="$LIBS"],[AC_MSG_ERROR([libunwind not found!])],[])
+       AC_CHECK_LIB([unwind],[unw_backtrace],[LIBS="$LIBS"],[AC_MSG_ERROR([libunwind not found!])],[])
        AC_CHECK_HEADER([libunwind.h],[AC_DEFINE([HAVE_LIBUNWIND_H],,[have libunwind.h])],
                [AC_MSG_ERROR([libunwind.h header not found!])])
        UNWINDLIB="-lunwind"