Error while compiling GCC 6.3.0 (LFS 8.0) on Arch Linux with GCC 7.1.0
 

Hello guys.

I was planning to make my own Linux From Scratch distribution.
For that I made myself an Arch Linux Virtual Machine with a virtual hard disk used for LFS, which I then copy on an USB Drive. Anyway, while compiling
GCC, at the end I got following error message:

[ALL ] /mnt/lfs/sources/gcc-6.3.0:
In function 'bool ubsan_use_new_style_p(location_t)':
[ERROR] /mnt/lfs/sources/gcc-6.3.0:
1474:23: error: ISO C++ forbids comparison between pointer and integer
[-fpermissive]
[ALL ] || xloc.file == '0' || xloc.file[0] == 'xff'
[ALL ] ^~~~


I really dont get this error message.
I would really appreciate it if someone of you guys could help me.

Sincerely,
nonick

post the output of the version script so we can check your host is complient

It looks like you're comparing pointers with text, which doesn't make sense.

I think line 1474 of whatever file contains the function, "bool ubsan_use_new_style_p(); may have some sort of error. It appears that there is or was line continuation and what the compiler seems to be seeing is a fragmented continuation of an existing if-test clause.

Most of the time you can't compile older gcc with newer one. The book specifies that a GCC version higher than one in the current book isn't supported. You can try and use gcc-6.4.0, which most likely has a patch for the issue.

Well, I tested GCC-7.1.0 now, it works fine.

I have tried building ch5 of lfs-8.0 with gcc-6.4.0 on fedora 26 and it worked for me.
Generally speaking you should not try to build a lfs toolchain that is older then the toolchain from your host.
You can boot from a livecd or use a chroot if your host is too new.