[gn] port d709dcc (LLVMFrontendDirective)

Author: nico

llvm/utils/gn/secondary/llvm/lib/Frontend/Directive/BUILD.gn

@@ -0,0 +1,7 @@
+static_library("Directive") {
+  output_name = "LLVMFrontendDirective"
+  deps = [
+    "//llvm/lib/Support",
+  ]
+  sources = [ "Spelling.cpp" ]
+}

llvm/utils/gn/secondary/llvm/lib/Frontend/OpenACC/BUILD.gn

@@ -1,6 +1,9 @@
 static_library("OpenACC") {
   output_name = "LLVMFrontendOpenACC"
-  deps = [ "//llvm/lib/Support" ]
+  deps = [
+    "//llvm/lib/Frontend/Directive",
+    "//llvm/lib/Support",
+  ]
   public_deps = [ "//llvm/include/llvm/Frontend/OpenACC:acc_gen" ]
   sources = [ "ACC.cpp" ]
 }