Here is result of version-check.sh




lfs@ubuntu:/home/yla$ sudo sh version-check.sh
bash, version 4.3.48(1)-release
/bin/sh -> /bin/bash
Binutils: (GNU Binutils for Ubuntu) 2.26.1
bison (GNU Bison) 3.0.4
/usr/bin/yacc -> /usr/bin/bison.yacc
bzip2, Version 1.0.6, 6-Sept-2010.
Coreutils: 8.25
diff (GNU diffutils) 3.3
find (GNU findutils) 4.7.0-git
GNU Awk 4.1.3, API: 1.1 (GNU MPFR 3.1.4, GNU MP 6.1.0)
/usr/bin/awk -> /usr/bin/gawk
gcc (Ubuntu 5.4.0-6ubuntu1~16.04.6) 5.4.0 20160609
g++ (Ubuntu 5.4.0-6ubuntu1~16.04.6) 5.4.0 20160609
(Ubuntu GLIBC 2.23-0ubuntu10) 2.23
grep (GNU grep) 2.25
gzip 1.6
Linux version 4.13.0-32-generic (buildd@lgw01-amd64-004) (gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.5)) #35~16.04.1-Ubuntu SMP Thu Jan 25 10:13:43 UTC 2018
m4 (GNU M4) 1.4.17
GNU Make 4.1
GNU patch 2.7.5
Perl version='5.22.1';
sed (GNU sed) 4.2.2
tar (GNU tar) 1.28
texi2any (GNU texinfo) 6.1
xz (XZ Utils) 5.1.0alpha
g++ compilation OK





Here is make -j4 output (just bottom lines)

make[2]: Entering directory '/mnt/lfs/sources/gcc/build/mpfr'
CDPATH="${ZSH_VERSION+.}:" && cd ../../mpfr && /bin/sh /mnt/lfs/sources/gcc/mpfr/missing aclocal-1.15 -I m4
/mnt/lfs/sources/gcc/mpfr/missing: line 81: aclocal-1.15: command not found
WARNING: 'aclocal-1.15' is missing on your system.
You should only need it if you modified 'acinclude.m4' or
'configure.ac' or m4 files included by 'configure.ac'.
The 'aclocal' program is part of the GNU Automake package:
<http://www.gnu.org/software/automake>
It also requires GNU Autoconf, GNU m4 and Perl in order to run:
<http://www.gnu.org/software/autoconf>
<http://www.gnu.org/software/m4/>
<http://www.perl.org/mpfr/aclocal.m4' failed
make[2]: *** [../../mpfr/aclocal.m4] Error 127
make[2]: Leaving directory '/mnt/lfs/sources/gcc/build/mpfr'
Makefile:4991: recipe for target 'all-mpfr' failed
make[1]: *** [all-mpfr] Error 2
make[1]: Leaving directory '/mnt/lfs/sources/gcc/build'
Makefile:863: recipe for target 'all' failed
make: *** [all] Error 2

The error from make is telling you what to do, you have missing software so install it.