您是否试图在***或google上搜索此问题？尝试在安装libmagickwand-dev后再次安装。

  apt-get install libmagickwand-dev 
 

I previously had an rmagick gem installation that works with ImageMagick. ImageMagick was installed from source with OpenMP disabled. This installation works without a hitch. However I attempted to uninstall rmagick and ImageMagick so that I could have a version that works with GraphicsMagick.

So I installed GraphicsMagick from source and disabled OpenMP feature once again. However, When I install rmagick I get the following:

Building native extensions.  This could take a while...
ERROR:  Error installing rmagick-2.13.1.gem:
        ERROR: Failed to build gem native extension.

        /usr/bin/ruby1.8 extconf.rb --build-opts --with-graphics-magick
checking for Ruby version >= 1.8.5... yes
checking for gcc... yes
checking for Magick-config... yes

Warning: Found a partial ImageMagick installation. Your operating system likely has some built-in ImageMagick libraries but not all of ImageMagick. This will most likely cause problems at both compile and runtime.
Found partial installation at: /usr
checking for ImageMagick version >= 6.4.9... yes
checking for HDRI disabled version of ImageMagick... 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... yes
checking for sys/types.h... yes
checking for wand/MagickWand.h... no

Can't install RMagick 2.13.1. Can't find MagickWand.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/ruby1.8

I have already attempted to run:

 export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig

And checking the contents of the folder pkgconfig:

freetype2.pc  GraphicsMagick.pc  GraphicsMagick++.pc  GraphicsMagickWand.pc  libpng15.pc  libpng.pc

What am I missing here?

have you tried to search for this issue on *** or google? Try to install again after installing libmagickwand-dev.

apt-get install libmagickwand-dev