When compiling gift in a subdirectory (like _build), the
generated file giftconfig.h is in _build, but when
compiling
the file is searched is the top directory.
e.g:
$cd gift
$mkdir _build
$cd _build
$rm ../lib/giftconfig.h # configure generated file
$../configure > /dev/null
$ls lib/giftconfig.h
lib/giftconfig.h
$make
...
../../lib/libgift.h:36:24: error: giftconfig.h: No such
file or directory
...