Re: [PATCH v2 0/1] MR1232: ntdll: Set the QoS class of the main Wine thread on macOS.

[Huw Davies (＠huw)]

@bshanks this is producing a compiler warning here:
```
gcc -m32 -c -o dlls/ntdll/unix/loader.o dlls/ntdll/unix/loader.c -Idlls/ntdll -Iinclude -D__WINESRC__ -DWINE_NO_LONG_TYPES \
  -D_NTSYSTEM_ -D_ACRTIMP= -DWINBASEAPI= -D_MSVCR_VER=0 -DBINDIR=\"/usr/local/bin\" \
  -DSYSTEMDLLPATH=\"\" -DDLL_TO_BINDIR=\"`tools/makedep -R /usr/local/lib/wine /usr/local/bin`\" \
  -DBIN_TO_DATADIR=\"`tools/makedep -R /usr/local/bin /usr/local/share/wine`\" -DWINE_UNIX_LIB -Wall -pipe \
  -fno-stack-protector -fno-strict-aliasing -Wdeclaration-after-statement -Wempty-body \
  -Wignored-qualifiers -Winit-self -Wno-pragma-pack -Wstrict-prototypes -Wtype-limits -Wvla \
  -Wwrite-strings -Wpointer-arith -gdwarf-4 -fno-omit-frame-pointer -fPIC \
  -fasynchronous-unwind-tables -O2 -g -Wno-deprecated-declarations -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0
dlls/ntdll/unix/loader.c:2339:9: warning: address of function 'pthread_attr_set_qos_class_np' will always evaluate to 'true' [-Wpointer-bool-conversion]
    if (pthread_attr_set_qos_class_np)
    ~~  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
dlls/ntdll/unix/loader.c:2339:9: note: prefix with the address-of operator to silence this warning
    if (pthread_attr_set_qos_class_np)
        ^
        &
1 warning generated.
```
Why do we need the test?

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/1232#note_13594