My environment is Fedora 21, i play around with hello tutorial from http://www.cogl3d.org/hello.html, it shows:
Building the example
If you save the above code to a file named hello.c then you can compile the example as follows:
gcc -o hello hello.c
pkg-config --cflags --libs cogl2 glib-2.0
but where can i find cogl2 library ?
If i doesn't include cogl library:
[xiaobai@xiaobai cogl]$ gcc -o hello hello.c `pkg-config --cflags --libs glib-2.0` 
hello.c:1:23: fatal error: cogl/cogl.h: No such file or directory
 #include <cogl/cogl.h>
                       ^
compilation terminated.
[xiaobai@xiaobai cogl]$ 
i tried dnf search cogl but there's only cogl, no such thing cogl2:
[xiaobai@xiaobai cogl]$ dnf search cogl
[sudo] password for xiaobai: 
================================================================= N/S Matched: cogl ==================================================================
cogl.x86_64 : A library for using 3D graphics hardware to draw pretty pictures
cogl.i686 : A library for using 3D graphics hardware to draw pretty pictures
cogl-doc.noarch : Documentation for cogl
cogl-devel.x86_64 : cogl development environment
cogl-devel.i686 : cogl development environment
[xiaobai@xiaobai cogl]$ 
I also search for cogl.h, no such cogl2 too:
[xiaobai@xiaobai yum]$ dnf provides */cogl.h
cogl-devel-1.18.2-9.fc21.x86_64 : cogl development environment
Repo        : @System
cogl-devel-1.18.2-9.fc21.i686 : cogl development environment
Repo        : fedora
cogl-devel-1.18.2-9.fc21.x86_64 : cogl development environment
Repo        : fedora
[xiaobai@xiaobai yum]$ 
I can't use pkg-config to find neither cogl nor cogl2:
[xiaobai@xiaobai cogl]$ pkg-config --cflags --libs cogl2 cogl
Package cogl2 was not found in the pkg-config search path.
Perhaps you should add the directory containing `cogl2.pc'
to the PKG_CONFIG_PATH environment variable
No package 'cogl2' found
Package cogl was not found in the pkg-config search path.
Perhaps you should add the directory containing `cogl.pc'
to the PKG_CONFIG_PATH environment variable
No package 'cogl' found
[xiaobai@xiaobai cogl]$ 
So i simply tried cogl:
$ gcc -o hello hello.c
pkg-config --cflags --libs glib-2.0-I/usr/include/cogl/
, it shows a lot of error messages:
[xiaobai@xiaobai cogl]$ gcc -o hello hello.c `pkg-config --cflags --libs glib-2.0` -I/usr/include/cogl/ 
hello.c:45:17: error: unknown type name ‘CoglOnscreen’
 frame_event_cb (CoglOnscreen *onscreen,
                 ^
hello.c:46:17: error: unknown type name ‘CoglFrameEvent’
                 CoglFrameEvent event,
                 ^
hello.c:47:17: error: unknown type name ‘CoglFrameInfo’
                 CoglFrameInfo *info,
                 ^
hello.c:59:11: error: unknown type name ‘CoglOnscreen’
 dirty_cb (CoglOnscreen *onscreen,
           ^
hello.c:60:17: error: unknown type name ‘CoglOnscreenDirtyInfo’
           const CoglOnscreenDirtyInfo *info,
                 ^
hello.c: In function ‘main’:
hello.c:86:14: warning: assignment makes pointer from integer without a cast
     data.ctx = cogl_context_new (NULL, &error);
              ^
hello.c:92:13: warning: assignment makes pointer from integer without a cast
     data.fb = cogl_onscreen_new (data.ctx, 640, 480);
             ^
hello.c:98:19: warning: assignment makes pointer from integer without a cast
     data.pipeline = cogl_pipeline_new (data.ctx);
                   ^
hello.c:100:17: warning: assignment makes pointer from integer without a cast
     cogl_source = cogl_glib_source_new (data.ctx, G_PRIORITY_DEFAULT);
                 ^
hello.c:105:39: error: ‘frame_event_cb’ undeclared (first use in this function)
                                       frame_event_cb,
                                       ^
hello.c:105:39: note: each undeclared identifier is reported only once for each function it appears in
hello.c:110:39: error: ‘dirty_cb’ undeclared (first use in this function)
                                       dirty_cb,
                                       ^
[xiaobai@xiaobai cogl]$ 
Any help is much appreciate.
[UPDATE] i've tried @CYB3R solution but still no luck:
[xiaobai@xiaobai cogl]$ pkg-config --cflags --libs cogl-2.0-experimental glib-2.0 
-pthread -I/usr/include/cogl -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng16 -I/usr/include/libdrm -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -lcogl -lgmodule-2.0 -pthread -lgdk_pixbuf-2.0 -lgobject-2.0 -lwayland-egl -lwayland-client -lgbm -ldrm -lwayland-server -lEGL -lX11 -lXext -lXdamage -lXfixes -lXcomposite -lXrandr -lglib-2.0 
[xiaobai@xiaobai cogl]$ gcc -pthread -I/usr/include/cogl -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng16 -I/usr/include/libdrm -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -lcogl -lgmodule-2.0 -pthread -lgdk_pixbuf-2.0 -lgobject-2.0 -lwayland-egl -lwayland-client -lgbm -ldrm -lwayland-server -lEGL -lX11 -lXext -lXdamage -lXfixes -lXcomposite -lXrandr -lglib-2.0 hello.c 
hello.c:45:17: error: unknown type name ‘CoglOnscreen’
 frame_event_cb (CoglOnscreen *onscreen,
                 ^
hello.c:46:17: error: unknown type name ‘CoglFrameEvent’
                 CoglFrameEvent event,
                 ^
... #same errors like previous
[xiaobai@xiaobai cogl]$ 
