[gn] port 24fc8f0 (and aec87a2)

Author: nico

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

@@ -0,0 +1,10 @@
+static_library("Atomic") {
+  output_name = "LLVMFrontendAtomic"
+  deps = [
+    "//llvm/lib/Analysis",
+    "//llvm/lib/IR",
+    "//llvm/lib/Support",
+    "//llvm/lib/TargetParser",
+  ]
+  sources = [ "Atomic.cpp" ]
+}

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

@@ -2,6 +2,7 @@ static_library("OpenMP") {
   output_name = "LLVMFrontendOpenMP"
   deps = [
     "//llvm/lib/Analysis",
+    "//llvm/lib/Frontend/Atomic",
     "//llvm/lib/Frontend/Offloading",
     "//llvm/lib/IR",
     "//llvm/lib/MC",