From: Christian Babeux <christian.babeux@efficios.com>
Date: Thu, 2 Aug 2012 22:55:11 +0000 (-0400)
Subject: Fix: Libtool fails to find dependent libraries when cross-compiling lttng-ust
X-Git-Tag: v2.0.5~3
X-Git-Url: http://git.lttng.org/?p=lttng-ust.git;a=commitdiff_plain;h=9834ab89cc80136e2e9f955ccd7037422dc2544a

Fix: Libtool fails to find dependent libraries when cross-compiling lttng-ust

This problem arise when cross compiling and linking libraries with
indirect libraries dependencies (such as liblttng-ust). This "bug" is
caused by an upstream modification in the libtool package on Debian
system. The libtool "link_all_deplibs" flag is set to "no" by default
on linux targets (AFAIK, other distros set it to "unknown").

The chosen solution is to detect such cases via the configure script
and automagically patch the libtool.m4 by forcing the "link_all_deplibs"
to "unknown".

This fixup can be disabled with the appropriate configure flag:

./configure --disable-libtool-linkdep-fixup

Sample configure output on affected systems:

checking for occurence(s) of link_all_deplibs = no in
         ./config/libtool.m4... 3
configure: WARNING: the detected libtool will not link all
           dependencies, forcing link_all_deplibs = unknown

Fixes: #321

Signed-off-by: Christian Babeux <christian.babeux@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/configure.ac b/configure.ac
index 5f4780cd..9d51e2e2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -39,6 +39,31 @@ version_description="New type of beer, 100% from Quebec, flavored with sapin bea
 AC_DEFINE_UNQUOTED([VERSION_NAME], [$version_name], [UST version name])
 AC_DEFINE_UNQUOTED([VERSION_DESCRIPTION], [$version_description], [UST version description])
 
+AC_PROG_GREP
+# libtool link_all_deplibs fixup. See http://bugs.lttng.org/issues/321.
+AC_ARG_ENABLE(libtool-linkdep-fixup,
+	AS_HELP_STRING([--disable-libtool-linkdep-fixup],
+			[disable the libtool fixup for linking all dependent libraries (link_all_deplibs)]),
+	libtool_fixup=$enableval,
+	libtool_fixup=yes)
+
+AS_IF([test "x$libtool_fixup" = "xyes"],
+	    [
+	    libtool_m4="$srcdir/config/libtool.m4"
+	    libtool_flag_pattern=".*link_all_deplibs\s*,\s*\$1\s*)"
+	    AC_MSG_CHECKING([for occurence(s) of link_all_deplibs = no in $libtool_m4])
+	    libtool_flag_pattern_count=$(grep -c "$libtool_flag_pattern\s*=\s*no" $libtool_m4)
+	    AS_IF([test $libtool_flag_pattern_count -ne 0],
+	    [
+		  AC_MSG_RESULT([$libtool_flag_pattern_count])
+		  AC_MSG_WARN([the detected libtool will not link all dependencies, forcing link_all_deplibs = unknown])
+		  sed -i "s/\($libtool_flag_pattern\)\s*=\s*no/\1=unknown/g" $libtool_m4
+		  ],
+		  [
+		  AC_MSG_RESULT([none])
+		  ])
+	    ])
+
 # Checks for programs.
 AC_PROG_CC
 AC_PROG_CXX