[cfe-dev] libcxx build warnings

["C. Bergström"]

Would a patch to clean-up some warnings in libcxx be accepted?  Any 
pitfalls I should be aware of before trying to fix these nits?
------------

libcxx/src/locale.cpp:846:48: warning: array subscript is of type 'char' 
[-Wchar-subscripts]
     return isascii(c) ? __classic_upper_table()[c] : c;
                                                ^~
libcxx/src/locale.cpp:860:55: warning: array subscript is of type 'char' 
[-Wchar-subscripts]
         *low = isascii(*low) ? __classic_upper_table()[*low] : *low;
                                                       ^~~~~
libcxx/src/locale.cpp:874:48: warning: array subscript is of type 'char' 
[-Wchar-subscripts]
     return isascii(c) ? __classic_lower_table()[c] : c;
                                                ^~
libcxx/src/locale.cpp:887:55: warning: array subscript is of type 'char' 
[-Wchar-subscripts]
         *low = isascii(*low) ? __classic_lower_table()[*low] : *low;
                                                       ^~~~~
[ 72%] Generating pathfortran-static-x86_64/__/libf/pxf/pxfgetcwd_c.o
libcxx/src/locale.cpp:1210:14: warning: comparison of integers of 
different signs: 'int' and 'unsigned int' [-Wsign-compare]
     return r != WEOF ? static_cast<char>(r) : dfault;
            ~ ^  ~~~~
libcxx/src/locale.cpp:1223:19: warning: comparison of integers of 
different signs: 'int' and 'unsigned int' [-Wsign-compare]
         *dest = r != WEOF ? static_cast<char>(r) : dfault;
                 ~ ^  ~~~~