Error when installing on macOS Big Sur 11.2

[ludomout]

When I try to install

gem install cairo

I get the following output:

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

    current directory: /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cairo-1.17.4/ext/cairo
/Users/ludo/.rbenv/versions/2.7.1/bin/ruby -I /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/2.7.0 -r ./siteconf20210203-60976-1miwu3o.rb extconf.rb
checking for GCC... yes
checking for Homebrew... yes
checking for cairo version (>= 1.2.0)... yes
*** 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=/Users/ludo/.rbenv/versions/2.7.1/bin/$(RUBY_BASE_NAME)
	--with-pkg-config
	--without-pkg-config
	--with-override-variables
	--without-override-variables
/Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:389:in `parse_pc': .pc doesn't exist: <expat> (PackageConfig::NotFoundError)
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:233:in `declaration'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:178:in `requires_private'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:504:in `block in all_required_packages'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:259:in `collect_requires'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:265:in `block in collect_requires'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:260:in `each'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:260:in `collect_requires'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:265:in `block in collect_requires'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:260:in `each'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:260:in `collect_requires'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:503:in `all_required_packages'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:283:in `collect_cflags'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:191:in `cflags_only_other'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:564:in `cflags_only_other'
	from /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/pkg-config-1.4.4/lib/pkg-config.rb:611:in `have_package'
	from extconf.rb:42:in `required_pkg_config_package'
	from extconf.rb:50:in `<main>'

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

  /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/extensions/x86_64-darwin-20/2.7.0/cairo-1.17.4/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cairo-1.17.4 for inspection.
Results logged to /Users/ludo/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/extensions/x86_64-darwin-20/2.7.0/cairo-1.17.4/gem_make.out

The mkmf.log file contains the following:

checking for GCC... -------------------- yes

"clang -o conftest -I/Users/ludo/.rbenv/versions/2.7.1/include/ruby-2.7.0/x86_64-darwin20 -I/Users/ludo/.rbenv/versions/2.7.1/include/ruby-2.7.0/ruby/backward -I/Users/ludo/.rbenv/versions/2.7.1/include/ruby-2.7.0 -I. -I/Users/ludo/.rbenv/versions/2.7.1/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT   -O3 -ggdb3 -Wall -Wextra -Wdeprecated-declarations -Wdivision-by-zero -Wimplicit-function-declaration -Wimplicit-int -Wmisleading-indentation -Wpointer-arith -Wshorten-64-to-32 -Wwrite-strings -Wmissing-noreturn -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wunused-variable -Wextra-tokens  -fno-common -pipe conftest.c  -L. -L/Users/ludo/.rbenv/versions/2.7.1/lib -L. -L/Users/ludo/.rbenv/versions/2.7.1/lib  -fstack-protector-strong -L/usr/local/lib     -lruby.2.7   "
checked program was:
/* begin */
1: #include "ruby.h"
2: 
3: int main(int argc, char **argv)
4: {
5:   return !!argv[argc];
6: }
/* end */

"clang -I/Users/ludo/.rbenv/versions/2.7.1/include/ruby-2.7.0/x86_64-darwin20 -I/Users/ludo/.rbenv/versions/2.7.1/include/ruby-2.7.0/ruby/backward -I/Users/ludo/.rbenv/versions/2.7.1/include/ruby-2.7.0 -I. -I/Users/ludo/.rbenv/versions/2.7.1/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT   -O3 -ggdb3 -Wall -Wextra -Wdeprecated-declarations -Wdivision-by-zero -Wimplicit-function-declaration -Wimplicit-int -Wmisleading-indentation -Wpointer-arith -Wshorten-64-to-32 -Wwrite-strings -Wmissing-noreturn -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wunused-variable -Wextra-tokens  -fno-common -pipe   -c conftest.c"
checked program was:
/* begin */
1: #include "ruby.h"
2: 
3: /*top*/
4: #ifndef __GNUC__
5: # error
6: |:/ === __GNUC__ undefined === /:|
7: #endif
/* end */

--------------------

checking for Homebrew... -------------------- yes

--------------------

have_package: checking for cairo version (>= 1.2.0)... -------------------- yes

--------------------

Error since updating to big sur 11.2
Any idea on how to fix this ?

[kou]

I think that you need to reinstall all your Homebrew Formulae after you update your macOS.

[ludomout]

I have already upgraded formulae without success.

[kou]

I have already upgraded formulae without success.

Does this mean that you failed to upgrade formulae? If so, it may be the problem.

[ludomout]

I have already upgraded formulae without success.

Does this mean that you failed to upgrade formulae? If so, it may be the problem.

Upgrade formulae successful but always the error gem install cairo

[kou]

Could you show output of the following command lines?

which pkg-config
pkg-config --debug --list-all
pkg-config --debug --cflags --libs cairo
pkg-config --debug --modversion cairo
pkg-config --debug --cflags --libs expat

[ludomout]

which pkg-config /usr/local/bin/pkg-config

pkg-config --debug --list-all
https://gist.github.com/ludomout/f7efffaee90d9d26b57d203c4224e7a2

pkg-config --debug --cflags --libs cairo
https://gist.github.com/ludomout/aac204510ed91e36b202f1b24877be44

pkg-config --debug --modversion cairo
https://gist.github.com/ludomout/2a6eab4b34b2e046046603d68e701d21

pkg-config --debug --cflags --libs expat
https://gist.github.com/ludomout/112e570368ee0bde7d118fe815624420

[kou]

Could you try gem install pkg-config; gem install cairo?

[ludomout]

All's good now.
Thank you :-)

[RobertDober]

Thank you for this really quick fix <3