[Info-vax] C99 updates to CRTL

[John Reagan]

Of course that system-wide DECC$SHR logical makes all images magically use the byte/word DECC$SHR.  The system-wide RTLMAP isnt needed as the compiler falls back to DECC$SHR.

Will we have chip specific variants of images in x86?  Probably for low level system images for Intel vs AMD.  I don't see it for others but I'd be open to it.  LLVM does provide for some flavors of multiple versions of the same routine with runtime selection of the right one.