[gn build] (manually) port 98f078324f (llvm-strings Opts.td)

llvm/utils/gn/secondary/llvm/tools/llvm-strings/BUILD.gn

@@ -1,6 +1,12 @@
 import("//llvm/tools/binutils_symlinks.gni")
+import("//llvm/utils/TableGen/tablegen.gni")
 import("//llvm/utils/gn/build/symlink_or_copy.gni")
 
+tablegen("Opts") {
+  visibility = [ ":llvm-strings" ]
+  args = [ "-gen-opt-parser-defs" ]
+}
+
 if (llvm_install_binutils_symlinks) {
   symlink_or_copy("strings") {
     deps = [ ":llvm-strings" ]
@@ -19,8 +25,10 @@ group("symlinks") {
 
 executable("llvm-strings") {
   deps = [
+    ":Opts",
     "//llvm/lib/IR",
     "//llvm/lib/Object",
+    "//llvm/lib/Option",
     "//llvm/lib/Support",
   ]
   sources = [ "llvm-strings.cpp" ]