Instead of using relative paths directly, use paths relative to
top_srcdir and top_builddir to refer to source files and built files,
respectively.
Note that the toplevel zlib configure script still does not have any
special support for out-of-tree builds. But now you can do
(cd contrib/minizip && autoreconf -fis)
mkdir -p BUILD/test
cp *.c *.h *.in zlib.map configure zlib.3 BUILD
cp test/*.c BUILD/test
(cd BUILD && ./configure --shared)
(cd BUILD && make)
mkdir -p BUILD/contrib/minizip
cd BUILD/contrib/minizip
../../../contrib/minizip/configure
make
While at it, move the include path and library path settings to
CPPFLAGS and LDFLAGS respectively instead of setting both in CFLAGS.
Thanks to Mike Frysinger for advice.
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