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Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

current directory:
/home/redmine/redmine-2.6.10-4/apps/redmine/htdocs/.bundle/ruby/2.3.0/gems/rmagick-2.13.4/ext/RMagick
/usr/bin/ruby2.3 -r ./siteconf20170608-23850-1xs1vx0.rb extconf.rb
checking for Ruby version >= 1.8.5... yes
checking for gcc... yes
checking for Magick-config... no
checking for pkg-config... yes
checking for ImageMagick version >= 6.4.9... yes
Package MagickCore was not found in the pkg-config search path.
Perhaps you should add the directory containing `MagickCore.pc'
to the PKG_CONFIG_PATH environment variable
No package 'MagickCore' found
Package MagickCore was not found in the pkg-config search path.
Perhaps you should add the directory containing `MagickCore.pc'
to the PKG_CONFIG_PATH environment variable
No package 'MagickCore' found
Package MagickCore was not found in the pkg-config search path.
Perhaps you should add the directory containing `MagickCore.pc'
to the PKG_CONFIG_PATH environment variable
No package 'MagickCore' found
Package MagickCore was not found in the pkg-config search path.
Perhaps you should add the directory containing `MagickCore.pc'
to the PKG_CONFIG_PATH environment variable
No package 'MagickCore' found
checking for stdint.h... *** 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)2.3
/usr/lib/ruby/2.3.0/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/2.3.0/mkmf.rb:587:in `try_cpp'
        from /usr/lib/ruby/2.3.0/mkmf.rb:1091:in `block in have_header'
        from /usr/lib/ruby/2.3.0/mkmf.rb:942:in `block in checking_for'
        from /usr/lib/ruby/2.3.0/mkmf.rb:350:in `block (2 levels) in postpone'
        from /usr/lib/ruby/2.3.0/mkmf.rb:320:in `open'
        from /usr/lib/ruby/2.3.0/mkmf.rb:350:in `block in postpone'
        from /usr/lib/ruby/2.3.0/mkmf.rb:320:in `open'
        from /usr/lib/ruby/2.3.0/mkmf.rb:346:in `postpone'
        from /usr/lib/ruby/2.3.0/mkmf.rb:941:in `checking_for'
        from /usr/lib/ruby/2.3.0/mkmf.rb:1090:in `have_header'
        from extconf.rb:212:in `<main>'

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

/home/redmine/redmine-2.6.10-4/apps/redmine/htdocs/.bundle/ruby/2.3.0/extensions/x86_64-linux/2.3.0/rmagick-2.13.4/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in
/home/redmine/redmine-2.6.10-4/apps/redmine/htdocs/.bundle/ruby/2.3.0/gems/rmagick-2.13.4
for inspection.
Results logged to
/home/redmine/redmine-2.6.10-4/apps/redmine/htdocs/.bundle/ruby/2.3.0/extensions/x86_64-linux/2.3.0/rmagick-2.13.4/gem_make.out

An error occurred while installing rmagick (2.13.4), and Bundler cannot
continue.
Make sure that `gem install rmagick -v '2.13.4'` succeeds before bundling.

In Gemfile:
  rmagick

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