[clang][driver][darwin] support -target with Mac Catalyst triple without OS version

Some users might omit the version and assume the compiler will target the initial
Mac Catalyst version.

(cherry picked from commit 3d0d7d8)

Author: hyp

clang/lib/Driver/ToolChains/Darwin.cpp

@@ -1807,7 +1807,12 @@ std::string getOSVersion(llvm::Triple::OSType OS, const llvm::Triple &Triple,
           << Triple.getOSName();
     break;
   case llvm::Triple::IOS:
-    Triple.getiOSVersion(Major, Minor, Micro);
+    if (Triple.isMacCatalystEnvironment() && !Triple.getOSMajorVersion()) {
+      Major = 13;
+      Minor = 1;
+      Micro = 0;
+    } else
+      Triple.getiOSVersion(Major, Minor, Micro);
     break;
   case llvm::Triple::TvOS:
     Triple.getOSVersion(Major, Minor, Micro);

clang/test/Driver/darwin-maccatalyst.c

@@ -1,9 +1,12 @@
 // RUN: %clang -target x86_64-apple-ios13.1-macabi -c %s -### 2>&1 | \
 // RUN:   FileCheck --check-prefix=CHECK-VERSION1 %s
+// RUN: %clang -target x86_64-apple-ios-macabi -c %s -### 2>&1 | \
+// RUN:   FileCheck --check-prefix=CHECK-VERSION1 %s
 // RUN: %clang -target x86_64-apple-ios13.0-macabi -c %s -### 2>&1 | \
 // RUN:   FileCheck --check-prefix=CHECK-ERROR %s
 // RUN: %clang -target x86_64-apple-ios12.0-macabi -c %s -### 2>&1 | \
 // RUN:   FileCheck --check-prefix=CHECK-ERROR %s
 
+// CHECK-VERSION1-NOT: error:
 // CHECK-VERSION1: "x86_64-apple-ios13.1.0-macabi"
 // CHECK-ERROR: error: invalid version number in '-target x86_64-apple-ios