Resolving external library interdependencies

[drwells]

Previously, I thought that the file names of scripts in cmake/configure established dependencies since we include them in sorted order:

dealii/CMakeLists.txt

Lines 122 to 129 in ed3f42a

	#
	# Feature configuration:
	#
	FILE(GLOB _configure_files "cmake/configure/configure_*.cmake")
	LIST(SORT _configure_files) # make sure to include in alphabetical order
	FOREACH(_file ${_configure_files})
	VERBOSE_INCLUDE(${_file})
	ENDFOREACH()

However, only about half of the files contain a digit in them (e.g., configure_0_threads.cmake is always first). We also have FEATURE_${_feature}_AFTER and FEATURE_${_feature}_DEPENDS which do error checking for interdependencies.

Is there any reason half of these don't have digits? If not then lets go ahead and add them.