OK. I just figured it out after some digging.
Here is the thing for Linux, to compile gtkmm programs you do this (I'm using gtkmm 2.4 and Code::Blocks version 1.0):
1.) In Code::Blocks, click on "Settings->Compiler".
2.) Under the "Compiler" tab click other options.
3.) On a new line type this:
`pkg-config --cflags gtkmm-2.4`
(note `` are back ticks (located beside "1" on American keyboards) and they have to be there).
4.) Click on "Linker" tab.
5.) In the "Other linker options" text area, enter this
(note `` are back ticks (located beside "1" on American keyboards) and they have to be there):
`pkg-config --libs gtkmm-2.4`
6.) Click on the "Other" tab.
7.) Change "Build method:" to "Work with Makefiles (GNU "make" is required)".
8.) Click "OK" and start building to your heart's contempt
-Gezim
Takeshi, you beat me! One thing you missed though, is step 6 and onwards. Plus my instructions are detailed