Can't install 'ihaskell-diagrams' using Cabal - haskell

Question

When I try to
cabal install ihaskell-diagrams
I get the error
The pkg-config package 'glib-2.0' is required but it could not be
found.
What is glib and how do I install it so that it is available for Cabal?
Resolving dependencies...
Configuring cairo-0.13.1.0...
Configuring glib-0.13.2.1...
Failed to install cairo-0.13.1.0
Build log ( /Users/Rax/.cabal/logs/cairo-0.13.1.0.log ):
[1 of 2] Compiling SetupWrapper ( /var/folders/b6/3rk65h797p7407x7d36sqn9c0000gn/T/cabal-tmp-57646/cairo-0.13.1.0/SetupWrapper.hs, /var/folders/b6/3rk65h797p7407x7d36sqn9c0000gn/T/cabal-tmp-57646/cairo-0.13.1.0/dist/setup/SetupWrapper.o )
[2 of 2] Compiling Main ( /var/folders/b6/3rk65h797p7407x7d36sqn9c0000gn/T/cabal-tmp-57646/cairo-0.13.1.0/dist/setup/setup.hs, /var/folders/b6/3rk65h797p7407x7d36sqn9c0000gn/T/cabal-tmp-57646/cairo-0.13.1.0/dist/setup/Main.o )
Linking /var/folders/b6/3rk65h797p7407x7d36sqn9c0000gn/T/cabal-tmp-57646/cairo-0.13.1.0/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 cairo-0.13.1.0...
setup: The pkg-config package 'cairo' version >=1.2.0 is required but it could
not be found.
Failed to install glib-0.13.2.1
Build log ( /Users/Rax/.cabal/logs/glib-0.13.2.1.log ):
[1 of 2] Compiling SetupWrapper ( /var/folders/b6/3rk65h797p7407x7d36sqn9c0000gn/T/cabal-tmp-57647/glib-0.13.2.1/SetupWrapper.hs, /var/folders/b6/3rk65h797p7407x7d36sqn9c0000gn/T/cabal-tmp-57647/glib-0.13.2.1/dist/setup/SetupWrapper.o )
[2 of 2] Compiling Main ( /var/folders/b6/3rk65h797p7407x7d36sqn9c0000gn/T/cabal-tmp-57647/glib-0.13.2.1/dist/setup/setup.hs, /var/folders/b6/3rk65h797p7407x7d36sqn9c0000gn/T/cabal-tmp-57647/glib-0.13.2.1/dist/setup/Main.o )
Linking /var/folders/b6/3rk65h797p7407x7d36sqn9c0000gn/T/cabal-tmp-57647/glib-0.13.2.1/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 glib-0.13.2.1...
setup: The pkg-config package 'glib-2.0' is required but it could not be
found.
cabal: Error: some packages failed to install:
cairo-0.13.1.0 failed during the configure step. The exception was:
ExitFailure 1
diagrams-cairo-1.3.0.5 depends on glib-0.13.2.1 which failed to install.
glib-0.13.2.1 failed during the configure step. The exception was:
ExitFailure 1
ihaskell-diagrams-0.3.1.0 depends on glib-0.13.2.1 which failed to install.
pango-0.13.1.0 depends on glib-0.13.2.1 which failed to install.

Answer 1

The confusion here results from the perhaps unclear error message: the missing components are not Cabal packages, but libraries that need to be separately installed.
Some of these libraries have their own dependencies, or installing them may reveal additional missing packages, so that the specific requirements on your system my be different; but in general, when you get an error that a "pig-config package" is missing, you will need to install it with your package manager (not Cabal).
For example,
brew install glib
brew install cairo
brew install pango
work for me and allow me to
cabal install ihaskell-diagrams
without further errors.