libtool: Apply upstream patch to set correct linkage on MIPS64

This libtool change ensures that ld uses the right machine emulation file,
which will allow to fix several MIPS64 n64 link failures, such as the one
currently visible on the libiscsi package.  Packages affected by this
problem will have to use <pkg>_AUTORECONF = YES to benefit from this libtool
fix, until they are fixed upstream.

Acked-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libtool/libtool-0001-mips64-n64-linking.patch

@@ -0,0 +1,47 @@
+sets correct linker ABI flags on MIPS64
+http://git.savannah.gnu.org/cgit/libtool.git/commit/?id=5f7f7d9615bf650cf99d581a33b3e18357f79951
+
+Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
+
+diff -ru libtool-2.4.2.orig/libltdl/m4/libtool.m4 libtool-2.4.2/libltdl/m4/libtool.m4
+--- libtool-2.4.2.orig/libltdl/m4/libtool.m4	2013-11-11 11:44:30.419396295 +0000
++++ libtool-2.4.2/libltdl/m4/libtool.m4	2013-11-11 11:44:07.055032308 +0000
+@@ -1312,6 +1312,38 @@
+   rm -rf conftest*
+   ;;
+ 
++mips64*-*linux*)
++  # Find out what ABI is being produced by ac_compile, and set linker
++  # options accordingly.
++  echo '[#]line '$LINENO' "configure"' > conftest.$ac_ext
++  if AC_TRY_EVAL(ac_compile); then
++    emul=elf
++    case `/usr/bin/file conftest.$ac_objext` in
++      *32-bit*)
++      emul="${emul}32"
++      ;;
++      *64-bit*)
++      emul="${emul}64"
++      ;;
++    esac
++    case `/usr/bin/file conftest.$ac_objext` in
++      *MSB*)
++      emul="${emul}btsmip"
++      ;;
++      *LSB*)
++      emul="${emul}ltsmip"
++      ;;
++    esac
++    case `/usr/bin/file conftest.$ac_objext` in
++      *N32*)
++      emul="${emul}n32"
++      ;;
++    esac
++    LD="${LD-ld} -m $emul"
++    fi
++  rm -rf conftest*
++  ;;
++
+ x86_64-*kfreebsd*-gnu|x86_64-*linux*|ppc*-*linux*|powerpc*-*linux*| \
+ s390*-*linux*|s390*-*tpf*|sparc*-*linux*)
+   # Find out which ABI we are using.