[Bug driver/100937] configure: Add --enable-default-semantic-interposition

[i at maskray dot me]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100937

--- Comment #6 from Fangrui Song <i at maskray dot me> ---
Then can you add a -fvisibility=protected variant which only applies to
non-weak defined functions?

Two issues need to be fixed:

(1): https://sourceware.org/bugzilla/show_bug.cgi?id=27973

__attribute__((visibility("protected"))) void *foo () {
  return (void *)foo;
}
% gcc -fpic -shared -fuse-ld=bfd a.s
/usr/bin/ld.bfd: /tmp/ccWPJCLw.o: relocation R_X86_64_PC32 against protected
symbol `foo' can not be used when making a shared object
/usr/bin/ld.bfd: final link failed: bad value
collect2: error: ld returned 1 exit status

(2): https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100593
[ELF] -fno-pic: Use GOT to take address of an external default visibility
function 


Distributions want fast C++ non-vague-linkage functions can enable this option.