[gn] port 32f7922 (LLVMOptDriver)

Author: nico

llvm/utils/gn/secondary/llvm/tools/opt/BUILD.gn

@@ -1,4 +1,5 @@
-executable("opt") {
+static_library("lib") {
+  output_name = "LLVMOptDriver"
   deps = [
     "//llvm/include/llvm/Config:llvm-config",
     "//llvm/lib/Analysis",
@@ -23,8 +24,13 @@ executable("opt") {
   ]
   sources = [
     "NewPMDriver.cpp",
-    "opt.cpp",
+    "optdriver.cpp",
   ]
+}
+
+executable("opt") {
+  sources = [ "opt.cpp" ]
+  deps = [ ":lib" ]
 
   # Support plugins.
   # FIXME: Disable dead stripping once other binaries are dead-stripped.