ct-ng build command fails, branch lx106 - xtensa-lx106-elf build

[developb]

Hi,
I have seen other people reporting the same issue but not exactly same to the detail.
I kept working around issues as they came, but stuck at a point. Below is the detail:

Basically, the reference for steps to build for me is from (https://w.electrodragon.com/w/ESP8266_GCC_SDK). I am working to setup bare metal build environment/ non os sdk for "ESP-01 8266" module. On Ubuntu 20.04.4 LTS virtual box (on windows machine).

1)Installed dependencies for next steps.
2)Downloaded lx106 branch and ensured access permissions issue do not arise.
3)./bootstrap; ./configure --prefix=pwd;make; make install
NOTE- In step "make", there was an issue in kconfig/zonf.hash.c compilation for which I corrected the source file and went ahead (data type mismatch in function definition vs function declaration)
4)./ct-ng xtensa-lx106-elf;./ct-ng build

Getting error at ct-ng build. It is trying to fetch mpc library from github but URL mismatch or fetch issue is happening. I installed manually the required mpc (multiprecision complex processing library) and edited .config file and somehow worked around this issue.

Next is issue with gcc: I do not have exact issue but after tweaking .config to bypass gcc build (CT_CC_GCC=n) and re-executing ./ct-ng build, below is the error:

.... ...
... ... ...
[DEBUG] ==> Executing: 'make' '-j5' '-l' '-C' 'gcc' 'libgcc.mk'
[ALL ] make[1]: Entering directory '/opt/esp8266/crosstool-NG-lx106/.build/xtensa-lx106-elf/build/build-cc-final/gcc'
[ALL ] make[1]: *** No rule to make target 'libgcc.mk'. Stop.
[ALL ] make[1]: Leaving directory '/opt/esp8266/crosstool-NG-lx106/.build/xtensa-lx106-elf/build/build-cc-final/gcc'
[ERROR]
[ERROR] >>
[ERROR] >> Build failed in step 'Installing final compiler'
[ERROR] >> called in step '(top-level)'
[ERROR] >>
[ERROR] >> Error happened in: CT_DoExecLog[scripts/functions@257]
[ERROR] >> called from: do_cc_core_backend[scripts/build/cc/gcc.sh@464]
[ERROR] >> called from: do_cc_for_host[scripts/build/cc/gcc.sh@595]
[ERROR] >> called from: main[scripts/crosstool-NG.sh@638]
[ERROR] >>
[ERROR] >> For more info on this error, look at the file: 'build.log'
[ERROR] >> There is a list of known issues, some with workarounds, in:
[ERROR] >> 'share/doc/crosstool-ng/ct-ng.1.20.0/B - Known issues.txt'
[ERROR]
[ERROR] (elapsed: 2:22.33)

Awaiting reply and support.

Thanks in advance.