ruby.hが見つからないエラー

railsをインストールし、rails newで新規プロジェクトを生成後、bundle updateをかけたときにエラーが発生しました。

$ sudo bundle update
The dependency tzinfo-data (>= 0) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for x86-mingw32, x86-mswin32, x64-mingw32, java. To add those platforms to the bundle, run `bundle lock --add-platform x86-mingw32 x86-mswin32 x64-mingw32 java`.
Fetching gem metadata from https://rubygems.org/............
Fetching gem metadata from https://rubygems.org/.
Resolving dependencies....
Using rake 12.3.3
Using concurrent-ruby 1.1.5
Using i18n 1.6.0
Using minitest 5.11.3
Using thread_safe 0.3.6
Using tzinfo 1.2.5
Using activesupport 5.2.3
Using builder 3.2.3
Using erubi 1.8.0
Using mini_portile2 2.4.0
Fetching nokogiri 1.10.3
Installing nokogiri 1.10.3 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    current directory: /var/lib/gems/2.5.0/gems/nokogiri-1.10.3/ext/nokogiri
/usr/bin/ruby2.5 -r ./siteconf20190724-10300-1bi1wo0.rb extconf.rb
checking if the C compiler accepts ... *** 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=/usr/bin/$(RUBY_BASE_NAME)2.5
	--help
	--clean
/usr/lib/ruby/2.5.0/mkmf.rb:456:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
	from /usr/lib/ruby/2.5.0/mkmf.rb:574:in `block in try_compile'
	from /usr/lib/ruby/2.5.0/mkmf.rb:521:in `with_werror'
	from /usr/lib/ruby/2.5.0/mkmf.rb:574:in `try_compile'
	from extconf.rb:138:in `nokogiri_try_compile'
	from extconf.rb:162:in `block in add_cflags'
	from /usr/lib/ruby/2.5.0/mkmf.rb:632:in `with_cflags'
	from extconf.rb:161:in `add_cflags'
	from extconf.rb:416:in `<main>'

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

  /var/lib/gems/2.5.0/extensions/x86_64-linux/2.5.0/nokogiri-1.10.3/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /var/lib/gems/2.5.0/gems/nokogiri-1.10.3 for inspection.
Results logged to /var/lib/gems/2.5.0/extensions/x86_64-linux/2.5.0/nokogiri-1.10.3/gem_make.out

An error occurred while installing nokogiri (1.10.3), and Bundler cannot continue.
Make sure that `gem install nokogiri -v '1.10.3' --source 'https://rubygems.org/'` succeeds before bundling.

In Gemfile:
  rails was resolved to 5.2.3, which depends on
    actioncable was resolved to 5.2.3, which depends on
      actionpack was resolved to 5.2.3, which depends on
        actionview was resolved to 5.2.3, which depends on
          rails-dom-testing was resolved to 2.0.3, which depends on
            nokogiri

指示された通りにmkmf.logを確認しました。

$ cat /var/lib/gems/2.5.0/extensions/x86_64-linux/2.5.0/nokogiri-1.10.3/mkmf.log
"gcc -o conftest -I/usr/include/x86_64-linux-gnu/ruby-2.5.0 -I/usr/include/ruby-2.5.0/ruby/backward -I/usr/include/ruby-2.5.0 -I. -Wdate-time -D_FORTIFY_SOURCE=2   -g -O2 -fdebug-prefix-map=/build/ruby2.5-Cn_Oyg/ruby2.5-2.5.1=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC  conftest.c  -L. -L/usr/lib/x86_64-linux-gnu -L. -Wl,-Bsymbolic-functions -Wl,-z,relro -Wl,-z,now -fstack-protector -rdynamic -Wl,-export-dynamic     -lruby-2.5  -lpthread -lgmp -ldl -lcrypt -lm   -lc "
checked program was:
/* begin */
1: #include "ruby.h"
2: 
3: int main(int argc, char **argv)
4: {
5:   return 0;
6: }
/* end */

前述の"ERROR: Failed to build gem native extension."とmkmf.logから、ruby.hが不足しているというエラーではないかと考えたので、ruby-devを導入しましたが、改善されません。
よろしくお願いします。

--ディストリビューション、バージョン情報追記
Ubuntu 18.04 LTS
ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-linux-gnu]
ruby-dev 2.5.1
rails 5.2.3