The HEAD branch of the CVS sources of GDB does not support the
DESTDIR variable.  I have attached a patch that fixes the 'install'
target in <mmalloc/Makefile.in>.

The next directory to fix would be <opcodes/po>.  I tried, but
the $(DESTDIR) expressions that I insert in Makefile.in disappear.
Something overwrites that Makefile.in, but there is no Makefile.am.
I haven't tried to understand what magic happens there.

See also PR 681.

-- 
Pierre Sarrazin <sarrazip @ sympatico . ca>