[PATCH] Fix memory leak in printf_positional

[Joseph Myers]

For memory leak bugs, if possible we add testcases to the testsuite that 
use mtrace.  That means (in addition to listing the test in tests as 
usual) adding $(objpfx)<test>-mem.out to tests-special, setting <test>-ENV 
to set MALLOC_TRACE, and adding the makefile rule that calls mtrace; see 
various existing examples.  (Of course the test should be something 
verified to fail the mtrace tests before the leak fix is applied; 
presumably it isn't hard to construct such a case that uses the malloc 
path here, and there might even be an existing test that could just have 
the pieces to use mtrace added to it.)

-- 
Joseph S. Myers
joseph@codesourcery.com