Processing input files and put them into output dir

[Suhachov Andrey]

Hello,

  I've some troubles with make. I want to do some thing, but I don't
  know, how to do it. I'm newbie in make, so sorry for stupid questions :)

  IDEA:
    I have *.in files. I want to convert them through M4 and some other
    filters into *.out files and put into output dir.

  For example:
    /path/to/m4
       1.m4
       2.m4
    /path/to/in-1/
       A/
         a1.in
         AB/
           ab1.in
   /path/to/in-2/
      B/
        b1.in

  When I execute make, I want to have following result:
    /outdir/
       A/
         a1.out
         AB/
           ab1.out
       B/
         b1.out

  I wrote Makefile:

    FILES = $(patsubst %.in,%.out,$(wildcard *.in))
    SUBDIRS = $(shell find ... ) # to give list of subdirs for current
                                 # dir
  
    vpath %.m4 /path/to/m4
  
    all: $(FILES) $(SUBDIRS) ;

    $(SUBDIRS):
       $(MAKE) -C $@

    %.out : %.in 1.m4 2.m4
       m4 -E -P .. | filter ... > $@
     
    .PHONY: all $(SUBDIRS)

  But I have a couple of problems:
    - If one of M4-files is missed, I've got error:
        Cannot find rule for `a1.out'
      instead of something like:
        Cannot find rule for `missed.m4'

    - I can't write code, to put *.out files into corresponding subdirs
      of OUTIDR. I want to have an ability to set OUTDIR as relative
      path (../outdir) and as absolute (/usr/local/...).
    
    - When I run `make -p', I've got VERY LONG list of actions. I think,
      there is some way to reduce it, but I don't know it...
      (I'm going to run make frequently, so performance is important)
      
 I appreciate any help.

-- 
Best regards,
 Andrew