Sad to hear that it is something in just my system.
The output of strace is clearly lengthy, I append the last lines - but I cannot see the point where the message is triggered
rename("/home/ralf/.config/audacious/config.tmp", “/home/ralf/.config/audacious/config”) = 0
open("/home/ralf/.mcs-backend", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/mcs-backend", O_RDONLY) = -1 ENOENT (No such file or directory)
mkdir("/home", 0755) = -1 EEXIST (File exists)
mkdir("/home/ralf", 0755) = -1 EEXIST (File exists)
mkdir("/home/ralf/.config", 0755) = -1 EEXIST (File exists)
mkdir("/home/ralf/.config/audacious", 0755) = -1 EEXIST (File exists)
open("/home/ralf/.config/audacious/config", O_RDONLY) = 10
fstat(10, {st_mode=S_IFREG|0644, st_size=0, …}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f6e6f035000
read(10, “”, 4096) = 0
close(10) = 0
munmap(0x7f6e6f035000, 4096) = 0
open("/home/ralf/.config/audacious/config.tmp", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 10
close(10) = 0
rename("/home/ralf/.config/audacious/config.tmp", “/home/ralf/.config/audacious/config”) = 0
open("/home/ralf/.mcs-backend", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/mcs-backend", O_RDONLY) = -1 ENOENT (No such file or directory)
mkdir("/home", 0755) = -1 EEXIST (File exists)
mkdir("/home/ralf", 0755) = -1 EEXIST (File exists)
mkdir("/home/ralf/.config", 0755) = -1 EEXIST (File exists)
mkdir("/home/ralf/.config/audacious", 0755) = -1 EEXIST (File exists)
open("/home/ralf/.config/audacious/config", O_RDONLY) = 10
fstat(10, {st_mode=S_IFREG|0644, st_size=0, …}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f6e6f035000
read(10, “”, 4096) = 0
close(10) = 0
munmap(0x7f6e6f035000, 4096) = 0
open("/home/ralf/.config/audacious/config.tmp", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 10
close(10) = 0
rename("/home/ralf/.config/audacious/config.tmp", “/home/ralf/.config/audacious/config”) = 0
open("/home/ralf/.mcs-backend", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/mcs-backend", O_RDONLY) = -1 ENOENT (No such file or directory)
mkdir("/home", 0755) = -1 EEXIST (File exists)
mkdir("/home/ralf", 0755) = -1 EEXIST (File exists)
mkdir("/home/ralf/.config", 0755) = -1 EEXIST (File exists)
mkdir("/home/ralf/.config/audacious", 0755) = -1 EEXIST (File exists)
open("/home/ralf/.config/audacious/config", O_RDONLY) = 10
fstat(10, {st_mode=S_IFREG|0644, st_size=0, …}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f6e6f035000
read(10, “”, 4096) = 0
close(10) = 0
munmap(0x7f6e6f035000, 4096) = 0
open("/home/ralf/.config/audacious/config.tmp", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 10
close(10) = 0
rename("/home/ralf/.config/audacious/config.tmp", “/home/ralf/.config/audacious/config”) = 0
write(7, “Populating included interfaces
“, 31) = 31
writev(2, {”/usr/bin/audacious2”, 19}, {": “, 2}, {“symbol lookup error”, 19}, {”: “, 2}, {”/usr/bin/audacious2", 19}, {": “, 2}, {“undefined symbol: index_new”, 27}, {”", 0}, {"", 0}, {"
", 1}], 10/usr/bin/audacious2: symbol lookup error: /usr/bin/audacious2: undefined symbol: index_new
) = 91
exit_group(127) = ?