[libc++] Replace incorrect visibility on a streambuf method

[ldionne]

Summary

In r336369, I replaced _LIBCPP_ALWAYS_INLINE by _LIBCPP_INLINE_VISIBILITY.
However, in one place, I replaced it by _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
and forgot to put it back before sending the review. Nobody spotted the subtle
mistake because the diff was so large. This broke the check-cxx-abilist test.

This commit fixes that.

[ldionne]

It's pretty obvious that this is the problem when looking at https://reviews.llvm.org/D48892 (grep for __pbump), but TBH I haven't been able to run the check-cxx-abilist test locally. Mine fails with like 500 differences, so there's got to be something I'm doing wrong.

[dexonsmith]

LGTM.

[dexonsmith]

In D48983#1153466, @ldionne wrote:

It's pretty obvious that this is the problem when looking at https://reviews.llvm.org/D48892 (grep for __pbump), but TBH I haven't been able to run the check-cxx-abilist test locally. Mine fails with like 500 differences, so there's got to be something I'm doing wrong.

It's possible no one has gotten that test working on Darwin before. I didn't know about it, anyway.

[ldionne]

I'm dropping this because I reverted https://reviews.llvm.org/D48892 until I figure out why it's breaking LLDB. The next time I submit https://reviews.llvm.org/D48892, I'll make sure to do it without this problem.

libcxx/include/streambuf

protected:
     // 27.6.2.3.3 Put area:
     _LIBCPP_INLINE_VISIBILITY char_type* pbase() const {return __bout_;}
     _LIBCPP_INLINE_VISIBILITY char_type* pptr()  const {return __nout_;}
     _LIBCPP_INLINE_VISIBILITY char_type* epptr() const {return __eout_;}
 
     inline _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
     void pbump(int __n) { __nout_ += __n; }
 
-    _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY
     void __pbump(streamsize __n) { __nout_ += __n; }
 
     inline _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
     void setp(char_type* __pbeg, char_type* __pend) {
         __bout_ = __nout_ = __pbeg;
         __eout_ = __pend;
     }