String-formatted relopts was never used before, but I've used it in buffering GiST index build patch and encountered with following compiler warnings:
reloptions.c:259: warning: initializer-string for array of chars is too long
reloptions.c:259: warning: (near initialization for ‘stringRelOpts[0].default_val’)
It is caused by definition of default field of relopt_string structure as 1-length character array. This seems to be a design flaw in the reloptions.c code. Any thoughts?