make maintainer-clean invokes gcc. It shouldn't, surely?

[Alan Mackenzie]

Hi, Emacs, 

I'm going mad.  I'm going round and round in circles in update hell.

I couldn't build Emacs last night or this morning, so in the end I
copied my entire emacs directory to somewhere new, and did 

   % make maintainer-clean

on it.  Guess what?  Somehow, it calls gcc in an attempt to compile
.../src/Makefile.c

make maintainer-clean is meant just to delete everything apart from the
raw source.  So how does it go about this?  rm -rf *.o *.elc ......???

<sarcasm>
Oh no!  make is far too sophisticated for something so vulgar.  No, the
proper way is to recursively invoke make on all the sub Makefiles,
obfuscating it with arguments like $(MFLAGS).  This has the advantage of
not being able to see what's going on.
</sarcasm>

Well, the ..../src/Makefile is also too sophisticated to do vulgar rm
-rf, so it therefore needs to compile Makefile.c.  In fact, it's trying
to compile Makefile.c in my original directory emacs, not the copy
emacs-300708.

What is the rock bottom clear-out-the-dross target doing invoking the
compiler on a file in a different directory tree?  Most of the times I
do a cvs update, I spend 5 to 10 hours trying to debug the make process.
Our make system is broken.  Either that, or I have descended into
lunacy.   

    find . -name Makefile | xargs wc

gives 13 files with these totals:

    4505 lines  17519 words  161027 bytes.

Would somebody like to convince me that Emacs's build complexity is
worth 4.5k lines of makefile, even given that a lot of them are
comments?  Emacs is NOT THAT COMPLICATED to build.

If anybody feels like helping me after this bad-tempered rant, please
help me.  What am I doing wrong?  How do I clear all built files out of
a directory tree?  How do I build Emacs?

-- 
Alan Mackenzie (Nuremberg, Germany).