From: Michal Schmidt <mschmidt@redhat.com>
Date: Tue, 13 Oct 2015 14:52:53 +0000 (+0200)
Subject: build: fix overlinking to libdw
X-Git-Tag: v228~204^2~2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7f7bfcf3cfc6f0d9fabffb63a44b607a7a040d57;p=thirdparty%2Fsystemd.git

build: fix overlinking to libdw

We have two AC_CHECK_LIB checks for libdw. The first one has an empty
action-if-found, so it defaults to adding "-ldw" to LIBS. LIBS are
applied to everything we build. But only systemd-coredump needs libdw.
It already links to ELFUTILS_LIBS correctly in Makefile.am.

Drop the first AC_CHECK_LIB check. The second check is sufficient.

Q: Don't we already use "-Wl,--as-needed" to eliminate overlinking?
A: We do, but it is effective only for executables, not for shared
   libraries. This is due to a libtool bug:
   https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=347650
---

diff --git a/configure.ac b/configure.ac
index c658c7fca3e..8f273c69905 100644
--- a/configure.ac
+++ b/configure.ac
@@ -788,14 +788,6 @@ if test "x${have_elfutils}" != xno ; then
                         AC_MSG_ERROR([*** ELFUTILS headers not found.])
                 fi])
 
-        AC_CHECK_LIB(
-                [dw],
-                [dwfl_begin],
-                [],
-                [if test "x$have_elfutils" = xyes ; then
-                        AC_MSG_ERROR([*** ELFUTILS libs not found.])
-                fi])
-
         AC_CHECK_LIB(
                 [dw],
                 [dwfl_core_file_attach],