desktop: do not complain about soffice command line options:

These are handled in the soffice wrapper script, but that is too stupid
to be able to filter these out, so just ignore them in soffice.bin.

(regression from 4efbd87e)

Also, print errors on stderr.

desktop/source/app/cmdlineargs.cxx

@@ -306,10 +306,16 @@ void CommandLineArgs::ParseCommandLine_Impl( Supplier& supplier )
                     }
 #if defined UNX
                     else
+                    // because it's impossible to filter these options that
+                    // are handled in the soffice shell script with the
+                    // primitive tools that /bin/sh offers, ignore them here
+                    if (!oArg.equalsIgnoreAsciiCaseAsciiL(RTL_CONSTASCII_STRINGPARAM("backtrace")) &&
+                        !oArg.equalsIgnoreAsciiCaseAsciiL(RTL_CONSTASCII_STRINGPARAM("strace")) &&
+                        !oArg.equalsIgnoreAsciiCaseAsciiL(RTL_CONSTASCII_STRINGPARAM("valgrind")))
                     {
-                        printf("Unknown option %s\n",
+                        fprintf(stderr, "Unknown option %s\n",
                             rtl::OUStringToOString(aArg, osl_getThreadTextEncoding()).getStr());
-                        printf("Run 'soffice --help' to see a full list of available command line options.\n");
+                        fprintf(stderr, "Run 'soffice --help' to see a full list of available command line options.\n");
                         SetBoolParam_Impl( CMD_BOOLPARAM_UNKNOWN, sal_True );
                     }
 #endif