[Docker] uClibc fails on configuration with missing en_US.UTF-8 locale

[falaleevms]

Host: ubuntu:16.04 and ubuntu:18.04

+ ./build-all.sh --no-elf32 --cpu hs38 --install-dir ../INSTALL-uclibc-hs38
 PASSED run_elf em4_dmips em6_dmips 
 Checking out GIT trees ...
 Downloading external dependencies...
 START little-endian uClibc: Thu Nov 21 12:13:47 UTC 2019
 Installing in /home/auto_user/arc_gnu/toolchain/../INSTALL-uclibc-hs38
 Installing Linux headers ...
   finished configuring Linux
   finished installing Linux headers
 Building binutils ...
   configuring...
   building...
   installing...
   generating PDF documentation...
 Building gcc-stage1 ...
   configuring...
   building...
   installing...
 Installing uClibc headers ...
 ERROR: uClibc header install was not successful. Please see
        "/home/auto_user/arc_gnu/logs/uclibc-build-2019-11-21-1213.log" for details.

See uclibc-build-2019-11-21-1213.log.txt

Reporduce:

# skip following command on ru20arcgnu1
docker load -i /slowfs/ru20arcgnu1/arcoss_verification/artifacts/ubuntu-16.04-reproduce-uclibc-headers-fail.tar

docker run -it --rm ubuntu-16.04-reproduce-uclibc-headers-fail
cd $HOME
/var/release-testing/toolchain-smoketest-tarball.sh

[abrodkin]

uClibc with enabled support of locales uses locale installed on build host and if it's missing (en_US.UTF-8 in particular) then uClibc fails to configure that way:

install -d libubacktrace/arc
make -C extra/locale locale_headers
gcc ../../extra/locale/gen_wc8bit.c  -o ../..//extra/locale/gen_wc8bit    -Os  -D__UCLIBC_GEN_LOCALE -I../..// -DCTYPE_PACKED=1 -DDO_WIDE_CHAR=1
echo "/home/auto_user/arc_gnu/uclibc-ng/extra/locale/../../extra/locale/charmaps/ASCII.pairs" > ../..//extra/locale/codesets.txt
echo ".../uclibc-ng/extra/locale/../../extra/locale/charmaps/ISO-8859-1.pairs" >> ../..//extra/locale/codesets.txt
../..//extra/locale/gen_wc8bit `cat ../..//extra/locale/codesets.txt` > ../..//extra/locale/c8tables.h
Makefile.in:163: recipe for target '../..//extra/locale/c8tables.h' failed
make[1]: *** [../..//extra/locale/c8tables.h] Error 1
Makefile.in:185: recipe for target 'headers' failed
make: *** [headers] Error 2

This happens because on a previous step gen_wc8bit didn't create proper c8tables.h:

# ./gen_wc8bit cat codesets.txt
could not find a UTF8 locale ... please enable en_US.UTF-8

# cat ./extra/locale/c8tables.h
could not find a UTF8 locale ... please enable en_US.UTF-8

That said for successful building of uClibc toolchain one has to have locale files for en_US.UTF-8 generated on build host. For that:

1. Make sure locale source files and utilities are installed. On Debian-based Linux distros apt-get install locales.
2. Generate en_US.UTF-8 files with:

# sed -i -e 's/# en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/' /etc/locale.gen
# locale-gen

Note typically normally installed desktop and server Linux distros have that locale generated, but in case of containers it might be missing. And Ubuntu containers do miss it so steps described above must be executed.