Add support for macOS (#771)

* use shm_open() instead of memfd_create() on macOS

malloc.h isn't a header on macOS

* Change OpenGL headers + create ifdef for DO_PROCLIST

macOS seems to already have the OpenGL functions defined, without the ifdef, it gives "ambiguous references" errors.

* macOS doesn't have ->gregs in uc_mcontext

and it doesn't have REG_RIP either
https://github.com/gperftools/gperftools/blob/master/m4/pc_from_ucontext.m4

* use getpid() to make memory file name unique

* #ifndef __APPLE__ for AF_PACKET and linux/if_packet.h

* Add include and link directories for macOS and link the OpenGL framework

* Add macOS CI

* Use newly added libslirp package from Homebrew

https://github.com/Homebrew/homebrew-core/pull/63412

* Use Apple's Clang instead of GNU GCC on macOS

* Add macOS build instructions to README

* Try to fix macOS undefined symbol

* snprintf doesn't take null terminator into account

* Map new memory on macOS for JIT

* Only use gcc-ar if using GNU Compiler

* re-add fastmem code - whoops!

* Fix style issue - use camelCase not snake_case

* Set Minimum macOS version

* Switch Minimum OS X version to 10.9

* Add macOS libpcap library name

* fix memory leak

* Fix binding keys in macOS

* Allow getting MAC address on macOS

melonDS on Linux uses AF_PACKET, which doesn't exist on macOS. Instead, this commit uses AF_LINK on macOS to get the MAC address.

* Remove unneeded macOS CI dependencies

* Build melonDS app bundle on macOS

Now it is no longer required to install the libraries on macOS, they come with the app bundle.

* fix macOS CI not being able to find macdeployqt

* copy melonDS.app with recursive because it's a folder

* Disable fastmem checkbox on macOS

* Disable fastmem by default in config

* forgot a semicolon

* Don't bundle libraries, causes issues on macOS <10.15

* Update README + allow finding version in Finder on macOS

* Make sure fastmem checkbox stays uncheckable

src/frontend/qt_sdl/LAN_PCap.cpp

@@ -33,7 +33,11 @@
 	#include <sys/types.h>
 	#include <ifaddrs.h>
 	#include <netinet/in.h>
-	#include <linux/if_packet.h>
+        #ifdef __APPLE__
+            #include <net/if_dl.h>
+        #else
+	    #include <linux/if_packet.h>
+        #endif
 #endif
 
 
@@ -66,6 +70,9 @@ const char* PCapLibNames[] =
 #ifdef __WIN32__
     // TODO: name for npcap in non-WinPCap mode
     "wpcap.dll",
+#elif defined(__APPLE__)
+    "libpcap.A.dylib",
+    "libpcap.dylib",
 #else
     // Linux lib names
     "libpcap.so.1",
@@ -276,6 +283,16 @@ bool Init(bool open_adapter)
                 struct sockaddr_in* sa = (sockaddr_in*)curaddr->ifa_addr;
                 memcpy(adata->IP_v4, &sa->sin_addr, 4);
             }
+            #ifdef __APPLE__
+            else if (af == AF_LINK)
+            {
+                struct sockaddr_dl* sa = (sockaddr_dl*)curaddr->ifa_addr;
+                if (sa->sdl_alen != 6)
+                    printf("weird MAC length %d for %s\n", sa->sdl_alen, curaddr->ifa_name);
+                else
+                    memcpy(adata->MAC, LLADDR(sa), 6);
+            }
+            #else
             else if (af == AF_PACKET)
             {
                 struct sockaddr_ll* sa = (sockaddr_ll*)curaddr->ifa_addr;
@@ -284,7 +301,7 @@ bool Init(bool open_adapter)
                 else
                     memcpy(adata->MAC, sa->sll_addr, 6);
             }
-
+            #endif
             curaddr = curaddr->ifa_next;
         }
     }