Daniel Gustafsson writes: > For me, the duplication aspect is the most troubling, since we'd still need the > xml2-config fallback and thus won't be able to simplify the code.
Yeah, but at least it's concentrated in a few lines in configure.in.
I think that the main objection to this is the documentation/confusion issues raised by Noah in that old thread. Still, we probably don't have much choice given that some distros are going to remove xml2-config. In that connection, Hugh's patch lacks docs which is entirely not OK, but the doc changes in Peter's old patch look workable.
Documentation can be added easily. :-)
I wonder whether we ought to try to align this with our documented procedure for falling back if you have no icu-config but want to use ICU; that part of the docs suggests setting ICU_CFLAGS and ICU_LIBS manually.
Unless your system has ICU installed in a non-standard location, there is no need to set those variables, as PKG_CHECK_MODULES will handle that for you. `./configure --help` also provides the relevant documentation on overriding pkg-config’s X_CFLAGS and X_LIBS.
The patch as it stands doesn't seem to support manually giving XML2_CFLAGS and XML2_LIBS, but it looks like it could easily be adjusted to allow that.
What I said for ICU also applies here (in fact, to all use of PKG_CHECK_MODULES). For the fallback, a minor rework is required.
The question is really whether we want to maintain a fallback to xml2-config. To give more context, I gave a more detailed assessment of the situation in an earlier email to this list. (Personally, I don’t think we should.)
Do note also that xslt-config will also be a problem at some point.
Also, I see that pkg.m4 says
dnl Note that if there is a possibility the first call to dnl PKG_CHECK_MODULES might not happen, you should be sure to include an dnl explicit call to PKG_PROG_PKG_CONFIG in your configure.ac
which we are not doing. We got away with that as long as there was only one PKG_CHECK_MODULES call ... but with two, I'd expect that the second one will fall over if the first one isn't executed.
