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author | Gregory M. Tuner <gmt@be-evil.net> | 2014-01-31 17:00:12 -0800 |
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committer | Gregory M. Tuner <gmt@be-evil.net> | 2014-01-31 17:00:12 -0800 |
commit | b29524a5454ffeefe8ab090e16bc8ea681ef056e (patch) | |
tree | 839a27eefada915624a81001d64947e8ecd0b770 /README | |
parent | readme update: less scary warnings, more up-to-date info (diff) | |
download | gmt-b29524a5454ffeefe8ab090e16bc8ea681ef056e.tar.gz gmt-b29524a5454ffeefe8ab090e16bc8ea681ef056e.tar.bz2 gmt-b29524a5454ffeefe8ab090e16bc8ea681ef056e.zip |
mention some caveats in the README
Signed-off-by: Gregory M. Tuner <gmt@be-evil.net>
Diffstat (limited to 'README')
-rw-r--r-- | README | 36 |
1 files changed, 36 insertions, 0 deletions
@@ -132,3 +132,39 @@ would be a practical impossibility for me to try the bazillions of permutations possible, and certain flags (i.e.: ldap), I'm just haven't had the chance to dink around with yet. +A final note: your MULTILIB_ABIS variable must be a superset of your ABI_X86 variable; +otherwise you are writing a check that your toolchain can't cash! The mapping between +them is: + +MULTILIB_ABIS ABI_X86 +============= ======= +amd64 64 +x86 32 +x32 x32 + +Another thing to be aware of is that a very significant number of bugs exist in +the upstream code pertaining to crossdev. Many of these have been worked around +in this overlay, often requiring nontrivial efforts to do so. + +But in general, if you have a crossdev toolchain whose ARCH matches the pseudo-ARCH +corresponding to your multilib targets, expect things to be less stable. + +The most likely scenario of this nature would be that you are on an ~amd64 profile +and have an i686-pc-linux-gnu crossdev toolchain. It helps somewhat to tell +binutils-config to generate "fake" targets for x86 by passing it the --x86 argument; +however, this is a half-measure. Autotools will pick the crossdev toolchain elements +up automatically almost every time. For things like "ar" this is not a problem and +you will get away with even really drastic things like accidentally using the +crossdev i686-pc-linux-gnu-gcc -- but know that this is wrong and will lead to problems +very frequently. + +Specific countermeasures are taken in this overlay to prevent the crossdev pkg-config +wrappers from being chosen by autotools, however, most build systems seem to (almost +desperately) want to use those, and this will lead to utter disaster very frequently +when it happens. Your best bet is simply to unmerge your i686-pc-linux-gnu crossdev +target once you are confident that your x86_64-pc-linux-gnu toolchain is consistently +doing the right thing with -m32. After all, technically speaking, at that point, +you really don't need it anymore. + +Long story short: keep your crossdev stuff in a prefix or a chroot or something, +unless you like fixing problems! |