That segment is for if you were building a script to compile
glibc automatically in order to run it on this system. The
"i?86" is a pattern; if the outut of uname -m matches it, it
will run the following commands until it gets to You probably
don't need it; it was specifically meant to figure out if your
architecture type was i386 since glibc doesn't support it
anymore. If you're building it in order to run it on a different
system that is not x86_64 (or to run it on this system, but
using only 32-bit instructions), then you want to force
compiling for i486. You can get rid the case structure
completely by converting case `uname -m` in i?86) echo "CFLAGS
+= -march=i486 -mtune=native" > configparms ;; echo "CFLAGS +=
-march=i486 -mtune=native" > configparms