Detect the header <getopt.h> in cmake, enabling the GETOPT_SUPPORT definition that allows the CLI fluidsynth program to use its features (like long arguments) when it is available, for instance in Windows/MinGW.

fluidsynth/CMakeLists.txt

@@ -121,6 +121,7 @@ check_include_file ( arpa/inet.h HAVE_ARPA_INET_H )
 check_include_file ( limits.h  HAVE_LIMITS_H )
 check_include_file ( pthread.h HAVE_PTHREAD_H )
 check_include_file ( signal.h HAVE_SIGNAL_H )
+check_include_file ( getopt.h HAVE_GETOPT_H )
 include ( TestInline )
 include ( TestVLA )
 include ( TestBigEndian )

fluidsynth/src/config.cmake

@@ -127,6 +127,9 @@
 /* Define to 1 if you have the <windows.h> header file. */
 #cmakedefine HAVE_WINDOWS_H @HAVE_WINDOWS_H@
 
+/* Define to 1 if you have the <getopt.h> header file. */
+#cmakedefine HAVE_GETOPT_H @HAVE_GETOPT_H@
+
 /* Define to enable JACK driver */
 #cmakedefine JACK_SUPPORT @JACK_SUPPORT@
 

fluidsynth/src/fluidsynth.c

@@ -30,6 +30,9 @@
 
 #if !defined(WIN32) && !defined(MACINTOSH)
 #define _GNU_SOURCE
+#endif
+
+#if defined(HAVE_GETOPT_H)
 #include <getopt.h>
 #endif
 
@@ -66,14 +69,13 @@ int option_help = 0;		/* set to 1 if "-o help" is specified */
 /*
  * support for the getopt function
  */
-#if !defined(WIN32) && !defined(MACINTOSH)
+#if defined(HAVE_GETOPT_H)
 #define GETOPT_SUPPORT 1
 int getopt(int argc, char * const argv[], const char *optstring);
 extern char *optarg;
 extern int optind, opterr, optopt;
 #endif
 
-
 /* Process a command line option -o setting=value, for example: -o synth.polyhony=16 */
 void process_o_cmd_line_option(fluid_settings_t* settings, char* optarg)
 {