-X_TOOLKIT_LIBS="-lXt"
-X_BASIC_LIBS="-lXext -lX11 -lXmu"
-
-dnl Check whether libXt has thread support. Some platforms may have
-dnl pthread support in libc, but no thread support in libXt/libX11.
-our_saved_LDFLAGS="$LDFLAGS"
-LDFLAGS="$X_LIBS $LDFLAGS"
-AC_CHECK_LIB(Xt, XtToolkitThreadInitialize, AC_DEFINE(X_THREAD_SUPPORT,1,[x thread supported]), , $X_PRE_LIBS $X_BASIC_LIBS $X_EXTRA_LIBS)
-LDFLAGS="$our_saved_LDFLAGS"
-
-dnl Check in -lXext for double buffering extensions to X11, and check
-dnl whether appropriate header files are present. (Some systems have one
-dnl but not the other.)
-our_saved_LDFLAGS="$LDFLAGS"
-LDFLAGS="$X_LIBS $LDFLAGS"
-AC_CHECK_LIB(Xext, XdbeQueryExtension, AC_DEFINE(HAVE_DBE_SUPPORT,1,[x dbe support]), , -lX11 "$X_EXTRA_LIBS")
-AC_CHECK_LIB(Xext, XmbufQueryExtension, AC_DEFINE(HAVE_MBX_SUPPORT,1,[x mbx support]), , -lX11 "$X_EXTRA_LIBS")
-LDFLAGS="$our_saved_LDFLAGS"
-our_saved_CPPFLAGS="$CPPFLAGS"
-CPPFLAGS="$X_CFLAGS $CPPFLAGS"
-AC_CHECK_HEADERS(X11/extensions/Xdbe.h X11/extensions/multibuf.h)
-CPPFLAGS="$our_saved_CPPFLAGS"
-