installing webkitgtk3: webkitgtk-3.0 version >=1.8 not found

[Blue Glacier]

Hello,

$ cabal install webkitgtk3
Resolving dependencies...
[1 of 2] Compiling SetupWrapper     ( /var/folders/27/1y1549hn7pqfvvd0zv7znvlm0000gn/T/webkitgtk3-0.12.6.1-5804/webkitgtk3-0.12.6.1/SetupWrapper.hs, /var/folders/27/1y1549hn7pqfvvd0zv7znvlm0000gn/T/webkitgtk3-0.12.6.1-5804/webkitgtk3-0.12.6.1/dist/setup/SetupWrapper.o )
[2 of 2] Compiling Main             ( /var/folders/27/1y1549hn7pqfvvd0zv7znvlm0000gn/T/webkitgtk3-0.12.6.1-5804/webkitgtk3-0.12.6.1/Setup.hs, /var/folders/27/1y1549hn7pqfvvd0zv7znvlm0000gn/T/webkitgtk3-0.12.6.1-5804/webkitgtk3-0.12.6.1/dist/setup/Main.o )
Linking /var/folders/27/1y1549hn7pqfvvd0zv7znvlm0000gn/T/webkitgtk3-0.12.6.1-5804/webkitgtk3-0.12.6.1/dist/setup/setup ...
[1 of 2] Compiling Gtk2HsSetup      ( Gtk2HsSetup.hs, dist/setup-wrapper/Gtk2HsSetup.o )
[2 of 2] Compiling Main             ( SetupMain.hs, dist/setup-wrapper/Main.o )
Linking dist/setup-wrapper/setup ...
Configuring webkitgtk3-0.12.6.1...
setup: The pkg-config package webkitgtk-3.0 version >=1.8 is required but it
could not be found.
Failed to install webkitgtk3-0.12.6.1
cabal: Error: some packages failed to install:
webkitgtk3-0.12.6.1 failed during the configure step. The exception was:
ExitFailure 1

What's going on there?
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