d/p/Fix-FTBFS-glibc2.30.patch: avoid issues with stropts in glibc >=2.30 (LP: #1855995)

The s3d code used stropts.h and thought it uses isastream, but that was wrong.

One might think 1 this is a valid call to check if something is a stream. But in reality this was never implemented 2. In glibc 2.30 this now got 3: "The obsolete and never-implemented XSI STREAMS header files <stropts.h> and <sys/stropts.h> have been removed." Since it always returned -1 it is equivalent in function to just drop the related lines.