Ever heard of Intel?
C compilers didn't offer an "AMD" CPU target* until AMD came out with the "AMD64" instruction set. Today we call this "x86_64" or "x64".
* Feel free to point out some custom multimedia vector extensions for Athlons or something, but the point remains.
The 1982 deal you speak of was actually pretty interesting: as a condition of the x86's use in the IBM PC, IBM requested a second source for x86 chips. AMD was that source, and so they cross-licensed the x86 in 1982 to allow the IBM PC project to proceed forward. This makes the Intel/AMD deal even more important for both companies: the PC market would never have developed without the cross-licensing, which would've been bad for all companies involved. This gave Intel an ongoing stake in AMD's success at least until the PC market consolidated on the x86 standard.