When the macro GETOPT_SUPPORT is disabled, the built binary cannot interpret the output file name "-" as a pipe.

[ghost]

FluidSynth version

fluidsynth -version
FluidSynth runtime version 2.3.6
Copyright (C) 2000-2024 Peter Hanappe and others.
Distributed under the LGPL license.
SoundFont(R) is a registered trademark of Creative Technology Ltd.

Describe the bug

On the command line, an output filename "-" following "-F" is misinterpreted as the start of another option.
In this case, an error will occur indicating an incorrect option specification.

This problem occurs when building with the macro GETOPT_SUPPORT disabled.
For example, when building Fluidsynth binaries for Windows with Microsoft Visual Studio.

Expected behavior

The command line option "-F -" is expected to be interpreted as outputting audio to a pipe.
The release binaries distributed on fluidsynth's github work as expected and do not have this issue.

Steps to reproduce

>fluidsynth.exe -F -
Expected argument to option -F found switch instead
Usage: fluidsynth [options] [soundfonts]
Try -h for help.

Additional context

This issue can be fixed by updating the code in fluidsynth.c as follows:

fluidsynth/src/fluidsynth.c

Line 511 in 66adce6

if(optarg[0] == '-')

- if(optarg[0] == '-') 
+ if ((optarg[0] == '-') && ((optarg[1] != '\0') || (c != 'F')))

[derselbst]

Thanks! Will be implemented as suggested.