The problem is not "gcc building system doesn't know cc-lfs can run on
pc", but "cc-lfs really cannot run on pc".
Let's stop anyone from thinking about "why not just tell the gcc
building system the fact".
I'm pretty sure "stage 2" libstdc++ (installed in ch6) is already fully
featured. The reason to rebuild the stage 3 libstdc++ (or entire
stage 3 gcc) is same as the reason to rebuild every packages in multiple
chapters: to "settle down" it.
Merge the content of
https://www.linuxfromscratch.org/lfs/faq.html#rebuild-ch8 into the book
as an explanation.
- Don't say "most building system", refine the dicussion for autoconf.
Other building systems may use a variant of triplet, or use a
completely different system designation.
- Explain why a triplet may contain 4 fields in detail. "Histroical
reason" is not really correct because 3-field triplet is still used
today for BSD, Fuchsia, IOS, Mac OS X (darwin), Solaris, etc.
- "machine" triplet to "system" triplet (strictly speaking, only the
first field in the triplet is for the machine).
Why we need to say "vendor can be omitted" explicitly: we mention "gcc
-dumpmachine". On some distros (like Ubuntu) the output has no vendor
field. If you think this is too nasty, please remove both.
"need to be cross compiled" alone does not make too much sense: we
compile these packages in chapter 8 anyway. The real reason forcing a
cross compilation is circular dependency: if building A needs B but
building B needs A, we'll have to cross compile at least one of A and B
or we won't be able to build either in the chroot.
Many distros have some customized things in gcc -dumpmachine. RHEL uses
x86_64-redhat-linux-gnu, and Ubuntu uses x86_64-linux-gnu ("vendor"
field omitted). So don't use "same" here, and also mention the "vendor"
field is sometimes omitted.
There are some discussion on gcc-help from someone (mis)using LFS to
build a "general" toolchain. Let's stop it before off-topic message got
into lfs-support.
- a wrong chapter in toolchain notes, and various text precisions
the option explanations of chapter 8 glibc (was labelled WIP)
git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@11961 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689
