XL: Use -qpic for position independent code (#14010)

According to XL C/C++ V9.0 documentation the default for -qpic/-qnopic
is platform-dependent.  It won't hurt to add the option on platforms
where it is the default, so always add it when we want position
independent code.
Merge topic 'aix-pic' into next

5c8c1d6 XL: Use -qpic for position independent code (#14010)