Xenomai runtime: report and mitigate when PLC cycle overruns.
Side effect :
_Log* macro was changed in plc_Xenomai_main.c,
and fixed in plc_Linux_main.c
<xsd:element name="Linux">
<xsd:complexType>
<xsd:attribute name="RealTime" type="xsd:boolean" use="optional" default="false"/>
%(toolchain_gcc)s
</xsd:complexType>
</xsd:element>