Patch by Robert Scheck <robert@fedoraproject.org> for libidn2 >= 2.0.0, which works
around the broken libtool of Debian. Multilib/multiarch systems like Fedora or Red
Hat Enterprise Linux are using /usr/lib64 for 64 bit libraries and /usr/lib is used
for 32 bit libraries. That allows to run 32 bit software on 64 bit systems. Debian
systems only use /usr/lib which contains only 32 or 64 bit systems depending on the
architecture.

Libtool hardcodes the runtime search path in a library (rpath), if the library that
is used for linking is not within the default system library path. The result is,
that if libtool.m4/configure files are generated by a Debian system, but used on a
Fedora or Red Hat Enterprise Linux 64 bit system for compiling, "-rpath /usr/lib64"
makes it into the binary.

Fedora and EPEL (for Red Hat Enterprise Linux) do not allow binaries with rpath, as
the Linux dynamic linker is usually smarter than the hardcoded path.

The fix for this issue is to add the optional /lib64 and /usr/lib64 directories at/
within libtool in front of the regular /lib and /usr/lib directories at the system
library path. These libtool information are hold in libtool.m4, which is generated
by running aclocal. As the content of libtool.m4 is included into configure during
a run of autoconf, libtool.m4 needs to be modified within the upstream build system
each time after a aclocal run - until Debian's libtool is fixed at Debian upstream.

Applying the fix is either possible by using the last hunk of the patch (the other
hunks are runtime-only if configure file has been already generated) or by running
the following sed command after each aclocal run within the upstream build system:

  sed -e 's@\(# Ideally, we could use ldconfig to report\)@# Add ABI-specific directories to the system library path.\n  sys_lib_dlsearch_path_spec="/lib64 /usr/lib64 /lib /usr/lib"\n\n  \1@' \
      -e 's@/lib /usr/lib $lt_ld_extra@$sys_lib_dlsearch_path_spec $lt_ld_extra@' -i libidn2-2.0.0/m4/libtool.m4

More information regarding this topic can be found for example at:

 - http://osdir.com/ml/bug-libtool-gnu/2009-12/msg00034.html
 - http://lists.gnu.org/archive/html/libtool/2009-01/msg00039.html
 - http://thread.gmane.org/gmane.comp.gnu.libtool.general/8339/focus=8345

--- libidn2-2.0.0/configure		2017-03-29 17:26:58.000000000 +0200
+++ libidn2-2.0.0/configure.rpath	2017-04-07 00:59:43.000000000 +0200
@@ -14266,6 +14266,9 @@
   # before this can be enabled.
   hardcode_into_libs=yes
 
+  # Add ABI-specific directories to the system library path.
+  sys_lib_dlsearch_path_spec="/lib64 /usr/lib64 /lib /usr/lib"
+
   # Ideally, we could use ldconfig to report *all* directores which are
   # searched for libraries, however this is still not possible.  Aside from not
   # being certain /sbin/ldconfig is available, command
@@ -14274,7 +14277,7 @@
   # appending ld.so.conf contents (and includes) to the search path.
   if test -f /etc/ld.so.conf; then
     lt_ld_extra=`awk '/^include / { system(sprintf("cd /etc; cat %s 2>/dev/null", \$2)); skip = 1; } { if (!skip) print \$0; skip = 0; }' < /etc/ld.so.conf | $SED -e 's/#.*//;/^[	 ]*hwcap[	 ]/d;s/[:,	]/ /g;s/=[^=]*$//;s/=[^= ]* / /g;s/"//g;/^$/d' | tr '\n' ' '`
-    sys_lib_dlsearch_path_spec="/lib /usr/lib $lt_ld_extra"
+    sys_lib_dlsearch_path_spec="$sys_lib_dlsearch_path_spec $lt_ld_extra"
   fi
 
   # We used to test for /lib/ld.so.1 and disable shared libraries on
--- libidn2-2.0.0/m4/libtool.m4		2017-02-15 10:54:29.000000000 +0100
+++ libidn2-2.0.0/m4/libtool.m4.rpath	2017-04-07 00:58:52.000000000 +0200
@@ -2866,6 +2866,9 @@
   # before this can be enabled.
   hardcode_into_libs=yes
 
+  # Add ABI-specific directories to the system library path.
+  sys_lib_dlsearch_path_spec="/lib64 /usr/lib64 /lib /usr/lib"
+
   # Ideally, we could use ldconfig to report *all* directores which are
   # searched for libraries, however this is still not possible.  Aside from not
   # being certain /sbin/ldconfig is available, command
@@ -2874,7 +2877,7 @@
   # appending ld.so.conf contents (and includes) to the search path.
   if test -f /etc/ld.so.conf; then
     lt_ld_extra=`awk '/^include / { system(sprintf("cd /etc; cat %s 2>/dev/null", \[$]2)); skip = 1; } { if (!skip) print \[$]0; skip = 0; }' < /etc/ld.so.conf | $SED -e 's/#.*//;/^[	 ]*hwcap[	 ]/d;s/[:,	]/ /g;s/=[^=]*$//;s/=[^= ]* / /g;s/"//g;/^$/d' | tr '\n' ' '`
-    sys_lib_dlsearch_path_spec="/lib /usr/lib $lt_ld_extra"
+    sys_lib_dlsearch_path_spec="$sys_lib_dlsearch_path_spec $lt_ld_extra"
   fi
 
   # We used to test for /lib/ld.so.1 and disable shared libraries on