diff --git a/configure.ac b/configure.ac
index aa18242a0c..bd83784892 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1214,10 +1214,14 @@ AG_GST_CHECK_FEATURE(MPLEX, [mplex], mplex, [
     dnl and mpeg2enc, we check for mplex on its own, too.
     dnl libmplex < 1.9rc? has fuzzy ABI, valgrind and other problems
     PKG_CHECK_MODULES(MPLEX, mjpegtools >= 1.9.0, [
+      dnl HACK because mplex 2.0.0 header files have a spurious 'include config.h'
+      touch config.h
       dnl switch over to c++ to test things
       AC_LANG_CPLUSPLUS
       OLD_CPPFLAGS="$CPPFLAGS"
-      CPPFLAGS="$CPPFLAGS $MPLEX_CFLAGS"
+      dnl HACK as above
+      CPPFLAGS_GOOD="$CPPFLAGS $MPLEX_CFLAGS"
+      CPPFLAGS="$CPPFLAGS_GOOD -I."
       AC_CHECK_HEADER(interact.hpp, [
         MPLEX_LIBS="$MPLEX_LIBS -lmplex2 $LIBM"
         OLD_LIBS="$LIBS"
@@ -1254,6 +1258,7 @@ main (int   argc,
 }
         ],[
           HAVE_MPLEX="yes"
+          CPPFLAGS="$CPPFLAGS_GOOD"
           AC_SUBST(MPLEX_CFLAGS)
           AC_SUBST(MPLEX_LIBS)
           AC_SUBST(MPLEX_LDFLAGS)