Include a startup source for FreeBSD

This seems to have been missed when the startup files were split out
during a refactor to support starting OpenRGB as a Windows service in
cf2df81.

Without this change, we see `ld: error: undefined symbol: main` when
compiling on FreeBSD.

I chose to name the file main_FreeBSD_Linux_MacOS instead of
main_Linux_MacOS_FreeBSD to keep the list alphabetical.

Author: Aesthetikx

OpenRGB.pro

@@ -523,7 +523,7 @@ contains(QMAKE_PLATFORM, linux) {
     SPDAccessor/EE1004Accessor_Linux.cpp                                                        \
     SPDAccessor/SPD5118Accessor_Linux.cpp                                                       \
     SuspendResume/SuspendResume_Linux_FreeBSD.cpp                                               \
-    startup/main_Linux_MacOS.cpp                                                                \
+    startup/main_FreeBSD_Linux_MacOS.cpp                                                        \
 
     #-------------------------------------------------------------------------------------------#
     # Set up install paths                                                                      #
@@ -647,6 +647,7 @@ contains(QMAKE_PLATFORM, freebsd) {
     serial_port/find_usb_serial_port_linux.cpp                                                  \
     AutoStart/AutoStart-FreeBSD.cpp                                                             \
     SuspendResume/SuspendResume_Linux_FreeBSD.cpp                                               \
+    startup/main_FreeBSD_Linux_MacOS.cpp                                                        \
 
     SOURCES -=                                                                                  \
     Controllers/SeagateController/RGBController_Seagate.cpp                                     \
@@ -716,7 +717,7 @@ macx {
     AutoStart/AutoStart-MacOS.cpp                                                               \
     qt/macutils.mm                                                                              \
     SuspendResume/SuspendResume_MacOS.cpp                                                       \
-    startup/main_Linux_MacOS.cpp                                                                \
+    startup/main_FreeBSD_Linux_MacOS.cpp                                                        \
 
     SOURCES += $$CONTROLLER_CPP_MACOS
 

startup/main_Linux_MacOS.cpp startup/main_FreeBSD_Linux_MacOS.cppstartup/main_Linux_MacOS.cpp renamed to startup/main_FreeBSD_Linux_MacOS.cpp

@@ -1,5 +1,5 @@
 /*---------------------------------------------------------*\
-| main_Linux_MacOS.cpp                                      |
+| main_FreeBSD_Linux_MacOS.cpp                              |
 |                                                           |
 |   Entry point for the OpenRGB application                 |
 |                                                           |