Cleanup LLVMTextAPI headers

Based on the output of iwyu. A full rebuild of llvm-project doesn't exhibit any
significant false dependencies.

The impact on preprocessed output is larger than expected, given the small
amount of changes

$ clang++ -E  -Iinclude -I../llvm/include ../llvm/lib/TextAPI/*.cpp -std=c++14 -fno-rtti -fno-exceptions | wc -l
before: 635319
After: 643716

Discourse thread on the topic: https://llvm.discourse.group/t/include-what-you-use-include-cleanup

1 files changed, 7 insertions, 2 deletions

diff --git a/llvm/lib/TextAPI/TextStubCommon.h b/llvm/lib/TextAPI/TextStubCommon.h
index 89ae5d5..aac2722 100644
--- a/llvm/lib/TextAPI/TextStubCommon.h
+++ b/llvm/lib/TextAPI/TextStubCommon.h
@@ -16,9 +16,9 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/YAMLTraits.h"
 #include "llvm/TextAPI/Architecture.h"
-#include "llvm/TextAPI/ArchitectureSet.h"
 #include "llvm/TextAPI/InterfaceFile.h"
-#include "llvm/TextAPI/PackedVersion.h"
+#include "llvm/TextAPI/Platform.h"
+#include "llvm/TextAPI/Target.h"
 
 using UUID = std::pair<llvm::MachO::Target, std::string>;
 
@@ -28,6 +28,11 @@ LLVM_YAML_IS_FLOW_SEQUENCE_VECTOR(UUID)
 LLVM_YAML_IS_FLOW_SEQUENCE_VECTOR(FlowStringRef)
 
 namespace llvm {
+
+namespace MachO {
+    class ArchitectureSet;
+    class PackedVersion;
+}
 namespace yaml {
 
 template <> struct ScalarTraits<FlowStringRef> {