[ucharfli]

 $ ncmpcpp
terminating with uncaught exception of type std::runtime_error: ctype_byname<char>::ctype_byname failed to construct for C
[1]    1511 abort      ncmpcpp

I share some detail with gdb.

 $ locale
LANG=en_US.UTF-8
LC_COLLATE="C"
LC_CTYPE="en_US.UTF-8"
LC_MONETARY="C"
LC_NUMERIC="C"
LC_TIME="C"
LC_MESSAGES="en_US.UTF-8"
LC_ALL=en_US.UTF-8

(gdb) r
Starting program: /usr/local/bin/ncmpcpp 
terminating with uncaught exception of type std::runtime_error: ctype_byname<char>::ctype_byname failed to 
construct for C

Program received signal SIGABRT, Aborted.
thrkill () at -:3
3       -: No such file or directory.
        in -
Current language:  auto; currently asm
(gdb) bt
#0  thrkill () at -:3
#1  0x00000c53c96bdc9d in _libc_abort () at /usr/src/lib/libc/stdlib/abort.c:52
#2  0x00000c53050cfa4a in abort_message (format=Variable "format" is not available.
) at /usr/src/lib/libcxxabi/src/abort_message.cpp:78
Die: DW_TAG_unspecified_type (abbrev = 30, offset = 590151)
        has children: FALSE
        attributes:
                DW_AT_name (DW_FORM_strp) string: "decltype(nullptr)"
Dwarf Error: Cannot find type of die [in module /usr/lib/libc++abi.so.0.0]

I did not understand much from here either.
I compiled Ncmpcpp in debug mode and found the problem.
file ncmpcpp.cpp

   107          std::locale::global(Charset::internalLocale());

I removed the code.

   107         // std::locale::global(Charset::internalLocale());

There's no problem now...
Is there anyone who has experienced the same problem?