Update .gitignore for Xcode

.gitignore

@@ -1,3 +1,4 @@
+/desmume/src/scmrev.h
 /desmume/src/frontend/windows/defaultconfig/scmrev.h
 /desmume/src/frontend/windows/.libs
 /desmume/src/frontend/windows/.obj
@@ -29,3 +30,30 @@ Makefile.in
 /desmume/src/frontend/posix/gtk/desmume
 /desmume/src/frontend/posix/gtk/doc/Makefile
 /desmume/src/frontend/posix/install-sh
+
+# Xcode
+
+## Build generated
+build/
+DerivedData/
+
+## Various settings
+*.pbxuser
+!default.pbxuser
+*.mode1v3
+!default.mode1v3
+*.mode2v3
+!default.mode2v3
+*.perspectivev3
+!default.perspectivev3
+xcuserdata/
+
+## Other
+*.moved-aside
+*.xcuserstate
+
+## Obj-C/Swift specific
+*.hmap
+*.ipa
+*.dSYM.zip
+*.dSYM