Well that is the 64 dollar question... It is likely that the amount of glyphosate present in human urine is at such a low level it will be ineffective as a weedkiller, but nonetheless, glyphosate binds tightly to soil particles and will persist for six months. There is a case study that shows glyphosate treated ground produced carrots two years later with glyphosate residue with them, so it may in fact persist for longer in some soils. The formulation of the product used (assuming its not basic, unadulterated glyphosate on its own, diluted appropriately) also makes a difference; the additional ingredients used in various brands may increase the potential for longer persistence.
Usually, though, it is recommended to add urine to a compost heap rather than using it fresh on cultivated areas; given the length of time for the compost to break down to a useable material, the risk of glyphosate contamination from that will likely be very low indeed. If you want to use your own urine as a direct fertilizer, switch to eating organic breads, cereals, flours and oils to avoid the larger doses of glyphosate commonly applied by growers as a dessicant on grain crops immediately prior to harvesting, and choose organic produce (including meat) wherever possible; whilst organic producers do still use chemicals, glyphosate is not among them, which means your own urine will contain much less (or none, if you only ever eat certified organic produce) assuming you're not using glyphosate yourself.