If the pd headers did this, then externals could compile on both <= 0.36 and 0.37 without changes:
/* Copyright (c) 1997-1999 Miller Puckette. * For information on usage and redistribution, and for a DISCLAIMER OF ALL * WARRANTIES, see the file, "LICENSE.txt," in this distribution. */
#ifndef __m_pd_h_
...
#define __m_pd_h_ #endif /* __m_pd_h_ */
This is most needed on m_pd.h, but I think it couldn't hurt in the other headers that are commonly used by externals: m_imp.h, s_stuff.h, g_canvas.h. Thomas Grill has had this change in the CVS devel_0_3? version for a while now, so I think its well tested.
.hc
________________________________________________________________________ ____
There is no way to peace, peace is the way. -A.J. Muste