precompiling inline mp to pdf?

[Christopher Creutzig <ccr@mupad.de>]

Salvete,

  for my latest project (almost done, so I don't need the answer for 
this one, but possibly in the future) I have compilation times which 
were dominated by Metapost until I switched to using --nomp most of the 
time and --automp --runs=2 whenever I changed something that results in 
changes to the Metapost stuff.  (I needed the --automp anyway, since to 
work around size limits in MetaPost I had to split the background into 
separate images, yet they had to influence one another via global 
variables -- increasing the memory limit to 80 MB made Metapost 
predictably freeze at unpredictable places in the run.)

  Now, my compile times are dominated by the mp to pdf conversion. 
Since pdf inclusion is fast (as expected), I'd like to use mptopdf once 
on each generated file and have ConTeXt include that.  Should I redefine 
\insertMPfile to first look for the pdf or is there a more clever way? 
(Note that I do want the automatic inclusion, since I'm passing the 
dimensions of external figures etc. to metapost and use the result in a 
background layer and/or as frame backgrounds.)

regards,
	Christopher Creutzig

PS: I didn't have time to analyze this when I came across it, but it 
seems that "texexec --automp file" consistently performs one TeX run too 
little.  In any case, the last thing it does is a metapost run, which 
doesn't seem sensible to me.