Use the same size computation when setting section protections than
when mapping it in the first place (reported by Nicholas Miell).

Make.rules: Replace RC_TLB by IDL_TLB_SRCS as tlb files can be used for other things than resources.

- Replace gl_FragColor with gl_FragData[0] for GLSL pixel shader output.
- Subtract 1 more constant from total GLSL allowed float constants to
  accommodate the PROJECTION matrix row that we reference.

- correct deleting the default container
- imported keys should be stored in their container, not just given to the caller
- tests for these changes

Remove some validation code that is already handled by a more generic
case at the end of the function.