[llvm-install-name-tool] Add -V flag

This diff adds -V alias for --version to make llvm-install-name-tool
consistent with other tools (llvm-objcopy, llvm-strip, etc).

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D87264

test/tools/llvm-objcopy/tool-version.test

@@ -5,6 +5,7 @@
 # RUN: llvm-strip -V | FileCheck --check-prefix=STRIP %s
 
 # RUN: llvm-install-name-tool --version | FileCheck %s
+# RUN: llvm-install-name-tool -V | FileCheck %s
 
 # OBJCOPY-DAG: {{ version }}
 # OBJCOPY-DAG: GNU objcopy

tools/llvm-objcopy/InstallNameToolOpts.td

@@ -32,3 +32,7 @@ def change: MultiArg<["-", "--"], "change", 2>,
 
 def version : Flag<["--"], "version">,
               HelpText<"Print the version and exit.">;
+
+def V : Flag<["-"], "V">,
+        Alias<version>,
+        HelpText<"Alias for --version">;