[libvirt] mingw pollution of DATADIR vs. configmake.h [was: [PATCH v10 08/19] backup: Parse and output checkpoint XML]

[adding bug-gnulib] On 7/24/19 12:55 AM, Eric Blake wrote: This causes a compilation failure on mingw, due to libvirt's "datatypes.h" including <winsock.h> after the point at which gnulib's "configmake.h" has already #define'd DATADIR into a string, but mingw's winsock.h tries to use DATADIR as a data-type tag name: make all-am make[1]: Entering directory '/home/berrange/src/virt/libvirt/src' CC conf/libvirt_conf_la-checkpoint_conf.lo In file included from /usr/i686-w64-mingw32/sys-root/mingw/include/objbase.h:66, from /usr/i686-w64-mingw32/sys-root/mingw/include/ole2.h:17, from /usr/i686-w64-mingw32/sys-root/mingw/include/wtypes.h:12, from /usr/i686-w64-mingw32/sys-root/mingw/include/winscard.h:10, from /usr/i686-w64-mingw32/sys-root/mingw/include/windows.h:97, from /usr/i686-w64-mingw32/sys-root/mingw/include/winsock2.h:23, from ../gnulib/lib/unistd.h:48, from ./driver.h:24, from ./datatypes.h:26, from conf/checkpoint_conf.c:28: /usr/i686-w64-mingw32/sys-root/mingw/include/objidl.h:12275:2: error: expected identifier or '(' before string constant } DATADIR; ^~~~~~~~~ make[1]: *** [Makefile:10127: conf/libvirt_conf_la-checkpoint_conf.lo] Error 1 And it's not the first time libvirt has run into this issue; I've found the following commits in 2015 that worked around it: https://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=976abdf6 https://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=bd205a90 Gnulib should work around this: perhaps "configmake.h" should include <unistd.h> first when built on mingw, as that is sufficient to trigger enough other headers to be included such that a later inclusion of <winsock.h> after "configmake.h" no longer runs into an issue with the DATADIR pollution breaking compilation, or perhaps gnulib can wrap <winsock.h> in such a way that it no longer depends on a tag name DATADIR. In the meantime, I'll push an obvious fix to libvirt to reorder the header inclusions to work around the problem. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org