On Wednesday 12 December 2007, Stepan Kasal wrote:
> On Tue, Dec 11, 2007 at 05:54:11PM -0500, Mike Frysinger wrote:
> > executing `pkg-config` is not friendly to cross-setups. you should use
> > AC_PATH_TOOL to setup the PKG_CONFIG environment variable and then use
> > that later on
>
> I was asking myself why "pkg-config" is not enough, the cross-compile
> case has not came to my mind.
> A small question remains: why full path? wouldn't AC_CHECK_TOOL suffice?
the purpose of using AC_CHECK_TOOL is not for the full path. AC_CHECK_TOOL
provides two things:
- allows people to explicitly set PKG_CONFIG
- searches for the binary with a ${build}- prefix
so the cross-compile case has people creating ${build}-pkg-config wrappers
which tell pkg-config to search the cross-compiler paths rather than the host
paths. i use that today with great success.
> In any case, this convinces me that using pkg.m4 is a good idea.
sure
> > > # These default values should work in most cases:
> > > : ${BLKID_LIBS='-lblkid'}
> > > : ${VOLUMEID_LIBS='-lvolume_id'}
> >
> > why only go half way ? i'd use pkg-config for everything.
>
> I don't think it is needed, AFAIK, mere "-lblkid" suffices for
> systems with GNU ld.so, as the rest is resolved by ld.so because of
> .so dependencies.
again, it probably will work in most cases, but in the cases where it wont,
there's no way for the user to control it without editing the configure
script.
> Until the blkid.pc is fixed (s/Requires/&.private/), the pkg-config
> version of BLKID_LIBS is even slightly worse than the fixed
> "-lblkid". (The build won't fail, but the binaries will have
> unneeded DT_NEEDED tags.)
is this really a big deal ?
> IIRC, the Karel has said that the pkg-config description in blkid is
> relatively new; with my patch, util-linux-ng build without
> pkg-config, unless a static build is required.
so have fallback code (i seem to recall the pkg config m4 macros have that)
when the .pc files are not available
-mike
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