checking for GTK... configure: error: Package requirements (gtk+-2.0 >= 2.0.0 gthread-2.0) were not met:

No package 'gtk+-2.0' found
No package 'gthread-2.0' found

Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.

Alternatively, you may set the environment variables GTK_CFLAGS
and GTK_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.