PR merged https://gitlab.com/gpsd/gpsd/-/merge_requests/578.patch
Subject: [PATCH] build: use CXXFLAGS for Qt
ensuring Qt C++ objects are compiled with the proper flag set
--- a/SConscript
+++ b/SConscript
@@ -1938,7 +1938,7 @@ libraries = [libgps_shared, packet_ffi_shared]
 # otherwise we have a mismash of objects in library
 if qt_env:
     qtobjects = []
-    qt_flags = qt_env['CFLAGS']
+    qt_flags = qt_env['CXXFLAGS']
     for c_only in ('--disable-excess-fp-precision',
                    '-fexcess-precision=standard',
                    '-Wmissing-prototypes',