Engine-953 Xcode fix: iOS SDK used for macOS build

build-mac/Subprojects/pEpASN1/pEpASN1.xcodeproj/project.pbxproj

@@ -1485,6 +1485,7 @@
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = NQLYU6MGPN;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SDKROOT = macosx;
 			};
 			name = Debug;
 		};
@@ -1494,6 +1495,7 @@
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = NQLYU6MGPN;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SDKROOT = macosx;
 			};
 			name = Debug_BUILD_ALL_SUPPORTED_ARCHS;
 		};
@@ -1503,6 +1505,7 @@
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = NQLYU6MGPN;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				SDKROOT = macosx;
 			};
 			name = Release;
 		};