Revert "Tidied up config.h.in to remove redundant guard"
Revert "Tidied up config.h.in to remove redundant guard"

This reverts commit a5247cfd2a63ac4ef4820a61d43af0fb10f722ae.

alecthomas/entityx,drewet/entityx,drewet/entityx,arvidsson/entityx,alecthomas/entityx,Bablawn3d5/entityx,jarrettchisholm/entityx,jaynus/entityx,drewet/entityx,arvidsson/entityx,arvidsson/entityx,asmodehn/entityx,jarrettchisholm/entityx,Bablawn3d5/entityx,Bablawn3d5/entityx,jaynus/entityx,asmodehn/entityx,jarrettchisholm/entityx,asmodehn/entityx,jaynus/entityx,asmodehn/entityx,alecthomas/entityx