check if libserial exists for unsupported libserial OS

src/include/86box/snd_opl.h

@@ -60,8 +60,10 @@ extern const device_t ymf289b_ymfm_device;
 extern const device_t ymf278b_ymfm_device;
 
 extern const device_t esfm_esfmu_device;
-
+#ifdef USE_LIBSERIALPORT
 extern const device_t ym_opl2board_device;
 #endif
 
+#endif
+
 #endif /*SOUND_OPL_H*/

src/include/86box/sound.h

@@ -209,8 +209,10 @@ extern const device_t tndy_device;
 extern const device_t wss_device;
 extern const device_t ncr_business_audio_device;
 
+#ifdef USE_LIBSERIALPORT
 /* External Audio device OPL2Board (Host Connected hardware)*/
 extern const device_t opl2board_device;
+#endif 
 
 #endif
 

src/sound/CMakeLists.txt

@@ -31,8 +31,6 @@ add_library(snd OBJECT
     snd_ps1.c
     snd_adlib.c
     snd_adlibgold.c
-    snd_opl2board.c
-    snd_opl_opl2board.cpp
     snd_ad1848.c
     snd_audiopci.c
     snd_azt2316a.c
@@ -173,19 +171,27 @@ if(OPL4ML)
     target_sources(snd PRIVATE midi_opl4.c midi_opl4_yrw801.c)
 endif()
  
-find_package(PkgConfig REQUIRED)
+find_package(PkgConfig )
-pkg_check_modules(SERIALPORT REQUIRED libserialport)
+pkg_check_modules(SERIALPORT  libserialport)
-if(APPLE)
-    include_directories(${LIBSERIALPORT_ROOT}/include)
-    target_link_libraries(86Box ${LIBSERIALPORT_ROOT}/lib/libserialport.dylib)
-elseif(WIN32)
-    include_directories(${SERIALPORT_INCLUDE_DIRS})
-    target_link_libraries(86Box ${SERIALPORT_LIBRARIES} SetupAPI)
-else()
-    include_directories(${SERIALPORT_INCLUDE_DIRS})
-    target_link_libraries(86Box ${SERIALPORT_LIBRARIES})
-endif()
 
+if(SERIALPORT_FOUND OR DEFINED LIBSERIALPORT_ROOT)
+    add_compile_definitions(USE_LIBSERIALPORT=1)
+
+    if(APPLE)
+        include_directories(${LIBSERIALPORT_ROOT}/include)
+        target_link_libraries(86Box ${LIBSERIALPORT_ROOT}/lib/libserialport.dylib)
+    elseif(WIN32)
+        include_directories(${SERIALPORT_INCLUDE_DIRS})
+        target_link_libraries(86Box ${SERIALPORT_LIBRARIES} SetupAPI)
+    else()
+        include_directories(${SERIALPORT_INCLUDE_DIRS})
+        target_link_libraries(86Box ${SERIALPORT_LIBRARIES})
+    endif()
+    target_sources(snd PRIVATE
+    snd_opl2board.c
+    snd_opl_opl2board.cpp
+)
+endif()
 
 add_subdirectory(resid-fp)
 target_link_libraries(86Box resid-fp)

src/sound/snd_opl.c

@@ -58,11 +58,12 @@ fm_driver_get(int chip_id, fm_drv_t *drv)
                 drv->priv = device_add_inst(&ymf262_ymfm_device, fm_dev_inst[fm_driver][chip_id]++);
             }
             break;
-
+#ifdef USE_LIBSERIALPORT
         case FM_OPL2BOARD:
             *drv      = ymfm_opl2board_drv;
             drv->priv = device_add_inst(&ym_opl2board_device, fm_dev_inst[fm_driver][chip_id]++);  
             break;
+#endif
         case FM_YMF289B:
             *drv      = ymfm_drv;
             drv->priv = device_add_inst(&ymf289b_ymfm_device, fm_dev_inst[fm_driver][chip_id]++);

src/sound/sound.c

@@ -153,7 +153,9 @@ static const SOUND_CARD sound_cards[] = {
     { &ct5880_device                },
     { &ad1881_device                },
     { &cs4297a_device               },
+#ifdef USE_LIBSERIALPORT /*The following devices required LIBSERIALPORT*/
     { &opl2board_device             },
+#endif     
     { NULL                          }
     // clang-format on
 };