Prevent libltdl.so from using 32-bit search path in 64-bit mode in Solaris OS.

--- libtool-2.4.6.orig/m4/libtool.m4	Tue Jan 20 17:15:19 2015
+++ libtool-2.4.6/m4/libtool.m4	Thu Apr 11 19:20:11 2019
@@ -1456,6 +1456,7 @@
   if AC_TRY_EVAL(ac_compile); then
     case `/usr/bin/file conftest.o` in
     *64-bit*)
+      SOLARIS_ISA_BITS=64
       case $lt_cv_prog_gnu_ld in
       yes*)
         case $host in
@@ -1478,6 +1479,9 @@
 	;;
       esac
       ;;
+    *32-bit*)
+      SOLARIS_ISA_BITS=32
+      ;;
     esac
   fi
   rm -rf conftest*
@@ -2995,6 +2999,12 @@
   hardcode_into_libs=yes
   # ldd complains unless libraries are executable
   postinstall_cmds='chmod +x $lib'
+  if test 32 = "$SOLARIS_ISA_BITS"; then
+    sys_lib_search_path_spec="/lib /usr/lib"
+  else
+    sys_lib_search_path_spec="/lib/64 /usr/lib/64"
+  fi
+  sys_lib_dlsearch_path_spec=$sys_lib_search_path_spec
   ;;
 
 sunos4*)