Fix SHOW_DEBUG macro checks to not throw warnings under clang

indra/llappearance/llavatarappearance.cpp

indra/llappearance/llavatarjointmesh.cpp

indra/llcharacter/lljoint.cpp

indra/llcharacter/lljointsolverrp3.cpp

indra/llcommon/lleventcoro.cpp

indra/llcommon/llprocess.cpp

indra/llcorehttp/_httppolicy.cpp

indra/llfilesystem/lldir.cpp

indra/llimagej2coj/llimagej2coj.cpp

indra/llmessage/llavatarname.cpp

indra/llmessage/llavatarnamecache.cpp

indra/llplugin/llpluginclassmedia.cpp

indra/llplugin/llpluginmessagepipe.cpp

indra/llplugin/llpluginprocessparent.cpp

indra/llprimitive/llprimitive.cpp

indra/llrender/llrender.cpp

indra/llui/llbutton.cpp

indra/llui/lldraghandle.cpp

indra/llui/lllineeditor.cpp

indra/llui/llmenugl.cpp