Check for amd64/atls.lib, and disable ActiveX 64bit component if not present.

configure.in

@@ -2674,9 +2674,8 @@ if test "$_os" = "WINNT"; then
         LINK_X64_BINARY=
         LIBMGR_X64_BINARY=
 
-        if test "$CL_X64" = ""; then
-            AC_MSG_CHECKING([for a x64 compiler])
-
+        AC_MSG_CHECKING([for a x64 compiler and libraries for 64bit ActiveX component])
+        if test "$CL_X64" = "" -a -f "$with_cl_home/atlmfc/lib/amd64/atls.lib"; then
             # Prefer native x64 compiler to cross-compiler, in case we are running
             # the build on a 64-bit OS.
             if "$with_cl_home/bin/amd64/cl.exe" -? </dev/null >/dev/null 2>&1; then
@@ -2692,12 +2691,12 @@ if test "$_os" = "WINNT"; then
                 LINK_X64_BINARY="$with_cl_home/bin/x86_amd64/link.exe"
                 LIBMGR_X64_BINARY="$with_cl_home/bin/x86_amd64/lib.exe"
             fi
-            if test "$BUILD_X64" = TRUE; then
-                AC_MSG_RESULT([found])
-            else
-                AC_MSG_RESULT([not found])
-                AC_MSG_WARN([Installation set will not contain the 64-bit Explorer extension])
-            fi
+        fi
+        if test "$BUILD_X64" = TRUE; then
+            AC_MSG_RESULT([found])
+        else
+            AC_MSG_RESULT([not found])
+            AC_MSG_WARN([Installation set will not contain the 64-bit Explorer extension])
         fi
         AC_SUBST(BUILD_X64)