[flang] Remove extra space added with --dependent-lib option

This patch fixes a bug with the --dependent-lib option where an
extra space is added to the directive causing linking to fail.

Author: DavidTruby

flang/lib/Frontend/FrontendActions.cpp

@@ -260,7 +260,7 @@ static void addDepdendentLibs(mlir::ModuleOp &mlirModule,
   auto builder = mlir::OpBuilder(mlirModule.getRegion());
   for (const std::string &lib : libs) {
     builder.create<mlir::LLVM::LinkerOptionsOp>(
-        mlirModule.getLoc(), builder.getStrArrayAttr({"/DEFAULTLIB:", lib}));
+        mlirModule.getLoc(), builder.getStrArrayAttr({"/DEFAULTLIB:" + lib}));
   }
 }
 

flang/test/Driver/dependent-lib.f90

@@ -10,7 +10,7 @@
 ! REDEFINE: %{triple} = aarch64-apple-darwin
 ! RUN: not %{compile} | FileCheck %s --check-prefixes=CHECK-NOWIN
 
-! CHECK: llvm.linker_options ["/DEFAULTLIB:", "libtest"]
+! CHECK: llvm.linker_options ["/DEFAULTLIB:libtest"]
 program test
 end program test
 ! CHECK-NOWIN: --dependent-lib is only supported on Windows