diff -ru mjpegtools-1.8.0-orig/configure.ac mjpegtools-1.8.0-no-jpeg-mmx/configure.ac
--- mjpegtools-1.8.0-orig/configure.ac	2006-11-19 17:11:41.000000000 +0100
+++ mjpegtools-1.8.0-no-jpeg-mmx/configure.ac	2006-11-20 13:56:47.000000000 +0100
@@ -197,29 +197,32 @@
   AC_MSG_ERROR([
 *** A directory must be specified for --with-jpeg-mmx option.])
 fi
-if test x$with_jpeg_mmx = x ; then
-  dnl Special case for building .deb's
-  if test -d ../jpeg-mmx ; then
-    with_jpeg_mmx=`pwd`/../jpeg-mmx
-  else
-    with_jpeg_mmx=/usr/local/src/jpeg-mmx
+if test x$with_jpeg_mmx != xno ; then
+  if test x$with_jpeg_mmx = x ; then
+    dnl Special case for building .deb's
+    if test -d ../jpeg-mmx ; then
+      with_jpeg_mmx=`pwd`/../jpeg-mmx
+    else
+      with_jpeg_mmx=/usr/local/src/jpeg-mmx
+    fi
   fi
-fi
 
 dnl
 dnl Look for the installed/specified copy
 dnl
 
-OLD_CFLAGS="$CFLAGS"
-OLD_LIBS="$LIBS"
-LIBS="$LIBS -L$with_jpeg_mmx"
-CFLAGS="$CFLAGS -I$with_jpeg_mmx"
-AC_CHECK_LIB(jpeg-mmx, jpeg_start_compress,
-   [ JPEG_LIBS="$LIBS -ljpeg-mmx"
-     JPEG_CFLAGS="-I$with_jpeg_mmx"
-       have_jpeg=true ],,)
-  LIBS="$OLD_LIBS"
-  CFLAGS="$OLD_CFLAGS"
+  OLD_CFLAGS="$CFLAGS"
+  OLD_LIBS="$LIBS"
+  LIBS="$LIBS -L$with_jpeg_mmx"
+  CFLAGS="$CFLAGS -I$with_jpeg_mmx"
+  AC_CHECK_LIB(jpeg-mmx, jpeg_start_compress,
+     [ JPEG_LIBS="$LIBS -ljpeg-mmx"
+       JPEG_CFLAGS="-I$with_jpeg_mmx"
+         have_jpeg=true ],,)
+    LIBS="$OLD_LIBS"
+    CFLAGS="$OLD_CFLAGS"
+
+fi
 
 dnl 
 dnl Look for _a_ jpeg lib that will work.