GCCE fixes (Bug 2971) : Remove IMPORT_C statements in ext_dat.h as these are not necessary within same module and cause "not constant" error with GCCE
This is a file used by ECom component tests. When the file is defined and exists then ECom
uses the TestHarnessDomainMember.
What goes in the file is irrelevant at the moment as we only test for the existence of the
file rather than its contents.