no EXPORT or GLOBAL section - unitialized variable being used!
also rearranged comment descriptions of meaning of optimizations (now tagfield clearly implies manyshapes)
eg. malloc(sizeof(t)) should be malloc(sizeof(struct t)) !!
single char ids like f, p should be avoided; renamed types as first, second, third etc
in a nice state now.. -- output file is selected and stored globally rather than being passed around all the time; -- implicit NULL tests are now explicit; -- some details of the generated code are different now.
added prototype rebuild stuff in a comment (for cutting and pasting); added decln, param and shape.
TRUE if we're optimizing (temporary code) or FALSE otherwise
in generated code
required a few changes to impln_declns