wooo, threadpool works

ChangeLog

@@ -37,7 +37,7 @@
 - better nprocs guesser
 - im_render() fixes to help the paintbox, some speedups too
 - added im_wbuffer2(), a new distributed threading system, and --vips-wbuffer2
-  to enable it
+  to enable it, thank you Christian
 
 15/1/10 started 7.21.1
 - added "written" callbacks, used to implement write to non-vips formats

TODO

@@ -1,8 +1,17 @@
-- do we need to wait for the last bg write to end?
-
 - make VipsThread opaque ... have a separate VipsThreadState struct holding
   stuff and only expose that
 
+- add progress feedback ... main thread should wake on every tile? or every
+  buffer write? or every second?
+
+- try with im_render(), ouch, that will be painful
+
+- switch other file sinks over, maybe have a shim layer?
+
+- switch im_iterate() over?
+
+- do we have other uses of threadgroup?
+
 - nip2 image display does not work with threading disabled
 
 - try a distributed worker model for image generation

libvips/iofuncs/threadpool.c

@@ -2,6 +2,8 @@
  * 
  * 18/3/10
  * 	- from threadgroup.c
+ * 	- distributed work allocation idea from Christian Blenia, thank you
+ * 	  very much
  */
 
 /*

po/README

@@ -20,15 +20,16 @@ and it would display as "Sevy imago os ...", with the "m" underlined.
 tips
 ----
 
-cd vips-7.x.x ; find */* -name "*.c" > po/POTFILES.in
-cd vips-7.x.x ; find */* -name "*.cc" >> po/POTFILES.in
-cd vips-7.x.x ; find */* -name "*.h" >> po/POTFILES.in
+cd vips-7.x.x 
+find */* -name "*.c" > po/POTFILES.in
+find */* -name "*.cc" >> po/POTFILES.in
+find */* -name "*.h" >> po/POTFILES.in
 
 	regenerate the list of files to search for strings
 
 intltool-update --pot
 
-	make a new vips-7.20.pot translation template from the sources
+	make a new vips-7.x.pot translation template from the sources
 
 :%s/msgstr ""/msgstr "Malkovich"/
 :%s/msgstr\[0\] ""/msgstr[0] "Malkovich"/