Asciidoctor Mathematical on Ubuntu 21.04

[ivanmanning]

Hi,

I'm trying to install asciidoctor-mathematical but I get an error.

If I run gem install asciidoctor-mathematical, I get the following error:

Building native extensions. This could take a while...
ERROR: Error installing asciidoctor-mathematical:
ERROR: Failed to build gem native extension.

current directory: /home/ivma/.rvm/gems/ruby-3.0.1/gems/mathematical-1.6.14/ext/mathematical

/home/ivma/.rvm/rubies/ruby-3.0.1/bin/ruby -I /home/ivma/.rvm/rubies/ruby-3.0.1/lib/ruby/3.0.0 -r ./siteconf20210526-38528-eex7lu.rb extconf.rb
checking for cmake... yes
checking for -lxml2... yes
checking for -lpangocairo-1.0... no
checking for libxml/tree.h in /include/libxml2,/usr/include/libxml2,/usr/local/include/libxml2,/usr/include/libxml2... yes
checking for libxml/parser.h in /include/libxml2,/usr/include/libxml2,/usr/local/include/libxml2,/usr/include/libxml2... yes
checking for libxml/xpath.h in /include/libxml2,/usr/include/libxml2,/usr/local/include/libxml2,/usr/include/libxml2... yes
checking for libxml/xpathInternals.h in /include/libxml2,/usr/include/libxml2,/usr/local/include/libxml2,/usr/include/libxml2... yes
-- The C compiler identification is GNU 10.3.0
-- The CXX compiler identification is GNU 10.3.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Deprecation Warning at CMakeLists.txt:19 (cmake_minimum_required):
Compatibility with CMake < 2.8.12 will be removed from a future version of
CMake.

Update the VERSION argument value or use a ... suffix to tell
CMake that the project does not need compatibility with older versions.

-- Found BISON: /usr/bin/bison (found version "3.7.5")
CMake Error at /usr/local/share/cmake-3.20/Modules/FindPackageHandleStandardArgs.cmake:230 (message):
Could NOT find FLEX (missing: FLEX_EXECUTABLE)
Call Stack (most recent call first):
/usr/local/share/cmake-3.20/Modules/FindPackageHandleStandardArgs.cmake:594 (_FPHSA_FAILURE_MESSAGE)
/usr/local/share/cmake-3.20/Modules/FindFLEX.cmake:264 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
CMakeLists.txt:62 (find_package)

-- Configuring incomplete, errors occurred!
See also "/home/ivma/.rvm/gems/ruby-3.0.1/gems/mathematical-1.6.14/ext/mathematical/mtex2MML/build/CMakeFiles/CMakeOutput.log".
/home/ivma/.rvm/gems/ruby-3.0.1/gems/make-0.3.1/bin/make:4:in <top (required)>': undefined local variable or method make' for main:Object (NameError)
from /home/ivma/.rvm/gems/ruby-3.0.1/bin/make:23:in load' from /home/ivma/.rvm/gems/ruby-3.0.1/bin/make:23:in

'
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.

Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/home/ivma/.rvm/rubies/ruby-3.0.1/bin/$(RUBY_BASE_NAME)
--with-xml2-dir
--without-xml2-dir
--with-xml2-include
--without-xml2-include=${xml2-dir}/include
--with-xml2-lib
--without-xml2-lib=${xml2-dir}/lib
--with-xml2lib
--without-xml2lib
--with-pangocairo-1.0-dir
--without-pangocairo-1.0-dir
--with-pangocairo-1.0-include
--without-pangocairo-1.0-include=${pangocairo-1.0-dir}/include
--with-pangocairo-1.0-lib
--without-pangocairo-1.0-lib=${pangocairo-1.0-dir}/lib
--with-pangocairo-1.0lib
--without-pangocairo-1.0lib
--use-system-mtex2MML
/home/ivma/.rvm/rubies/ruby-3.0.1/lib/ruby/3.0.0/fileutils.rb:494:in realpath': No such file or directory @ rb_check_realpath_internal - /home/ivma/.rvm/gems/ruby-3.0.1/gems/mathematical-1.6.14/ext/mathematical/mtex2MML/build/libmtex2MML.a (Errno::ENOENT) from /home/ivma/.rvm/rubies/ruby-3.0.1/lib/ruby/3.0.0/fileutils.rb:494:in copy_entry'
from /home/ivma/.rvm/rubies/ruby-3.0.1/lib/ruby/3.0.0/fileutils.rb:471:in block in cp_r' from /home/ivma/.rvm/rubies/ruby-3.0.1/lib/ruby/3.0.0/fileutils.rb:1597:in block in fu_each_src_dest'
from /home/ivma/.rvm/rubies/ruby-3.0.1/lib/ruby/3.0.0/fileutils.rb:1611:in fu_each_src_dest0' from /home/ivma/.rvm/rubies/ruby-3.0.1/lib/ruby/3.0.0/fileutils.rb:1595:in fu_each_src_dest'
from /home/ivma/.rvm/rubies/ruby-3.0.1/lib/ruby/3.0.0/fileutils.rb:470:in cp_r' from extconf.rb:80:in

'

To see why this extension failed to compile, please check the mkmf.log which can be found here:

/home/ivma/.rvm/gems/ruby-3.0.1/extensions/x86_64-linux/3.0.0/mathematical-1.6.14/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /home/ivma/.rvm/gems/ruby-3.0.1/gems/mathematical-1.6.14 for inspection.
Results logged to /home/ivma/.rvm/gems/ruby-3.0.1/extensions/x86_64-linux/3.0.0/mathematical-1.6.14/gem_make.out

And if I run sudo apt-get -qq -y install bison flex libffi-dev libxml2-dev libgdk-pixbuf2.0-dev libcairo2-dev libpango1.0-dev fonts-lyx cmake, I get the following error:

E: Unable to correct problems, you have held broken packages.

I'm using the latest version of asciidoctor

Asciidoctor 2.0.12 [https://asciidoctor.org]
Runtime Environment (ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [x86_64-linux-gnu]) (lc:UTF-8 fs:UTF-8 in:UTF-8 ex:UTF-8)

And the latest version of Ruby

ruby 3.0.1p64 (2021-04-05 revision 0fb782ee38) [x86_64-linux]

What am I doing wrong?

P.S. I don't know if this changes anything, but the Linux is installed as virtual OS on VirtualBox.

[ivanmanning]

After reverting Ubuntu to 20.04.2.0 LTS (Focal Fossa), everything worked ok.