Pressure suits were (and are) created for high-G flying, so that pilots don't black out.
G-suits came a bit later than pressure suits in aeronautics; the first pressure-maintaining suits were introduced in the 1930s simply to allow for high altitude flying (but saw little practical application), while pressure trousers for regulating blood flow were operationally introduced only after WWII.
In "Squire of Gothos" already, we see a beltpack supposedly capable of providing it. Simple compressed air might suffice, but no doubt future technology could use dense liquid oxygen and then extensively recycle the air. It could all be easily built into this putative helmet to be worn with the uniform. Something similar seems to be going on with the life support belts, too.
In a semi-conventional setup, I think the big bottleneck would be gloves. If the uniform is to provide vacuum survivability in an emergency, it's simple to don a survival helmet in a matter of seconds (provided one is handily available in a nearby locker), but it takes quite a while to get pressure gloves on, especially when pressure is lost. This regardless of whether the gloves provide pressure by virtue of being airtight (in which case they would require their own supply of air or other pressure gas) or simply tight. The act that is supposed to preserve one's manipulative abilities requires the very abilities! What to do? Pull the helmet on to preserve consciousness, only to find out one cannot pull on the gloves any more because the hands no longer work? Or pull on the gloves while one still can, only to succumb to loss of air, the pain in your ears, the pressure differential between your lungs and the environment?
If the gloves are made easily donnable with materials technology (say, they shrink in place automagically), one might just as well have the whole survival gear be made in this manner, and have it stashed in a locker, rather than force the user to wear an uncomfortably tight survival suit 24/7.