ctype(3): Actually conditionalize guard page on shared libc.
Apparently we build the libc .o files with -fPIC too (I guess this is
so that libc.a works in position-independent executables? but why
don't they just use libc_pic.a?), so use a purpose-built cpp macro
_CTYPE_DYNAMIC for this instead of using __PIC__.
Now this shows the right symbol sizes:
$ readelf -s ctype_.pico | grep _C_ctype_tab_guarded_
3: 0000000000000000 4610 OBJECT LOCAL DEFAULT 11 _C_ctype_tab_guarded_
$ readelf -s ctype_.po | grep _C_ctype_tab_guarded_
3: 0000000000000000 514 OBJECT LOCAL DEFAULT 7 _C_ctype_tab_guarded_
$ readelf -s ctype_.o | grep _C_ctype_tab_guarded_
3: 0000000000000000 514 OBJECT LOCAL DEFAULT 7 _C_ctype_tab_guarded_
PR lib/58208: ctype(3) provides poor runtime feedback of abuse
UnifiedSplitRaw
