Use of MMP_RULES+= "OPTION ARMCC ..." and others in .pro file overrides definitions in symbian.conf

If someone in their .pro files writes MMP_RULES += "OPTION ARMCC <some option>", we lose our configuration options "OPTION ARMCC --visibility_inlines_hidden --fpu softvfp --diag_suppress 111,185,191,368,1293,1294,2874". Therefore if anyone wants to do this, they also have to make sure they take our configuration options from symbian.conf

Certainly we want to retain --visibility_inlines_hidden. Do we want to separate out optional from mandatory compiler flags? The problem is with that scheme, you could quite easily just want to add one option, and you'd end up accidentially replacing some of our options that we thought you might want to override. Or alternately, you might want to override an option that we considered mandatory. (This is why Symbian has OPTION and OPTION_REPLACE, to make it clear what you're doing)

Possible fix - append theirs to ours (prepend in the GCCE case?). Then they would just do what we do, which is to override options on the command line be repeating the same option but later, which causes the compiler/linker/whatever to use that instead.