File link-llvm9.patch of Package include-what-you-use

From 589cf3836ed663b1386ed071e446d8da0fc3ef4b Mon Sep 17 00:00:00 2001
From: Aaron Puchert <aaronpuchert@alice-dsl.net>
Date: Fri, 1 Nov 2019 17:23:54 +0100
Subject: [PATCH] Link with clang-cpp if only that is available

Since LLVM 9, the Clang component libraries are also linked into
clang-cpp, which provides the full C++ API [1]. So we link with that
if it is available and the component libraries are not.

[1] http://releases.llvm.org/9.0.0/tools/clang/docs/ReleaseNotes.html#build-system-changes
---
 CMakeLists.txt | 43 ++++++++++++++++++++++++-------------------
 1 file changed, 24 insertions(+), 19 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 15c48cd..a4b02ba 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -100,25 +100,30 @@ if (MSVC)
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /bigobj /EHsc")
 endif()
 
-target_link_libraries(include-what-you-use
-  PRIVATE
-  clangBasic
-  clangLex
-  clangAST
-  clangSema
-  clangFrontend
-  clangDriver
-
-  # Revision [1] in clang moved PCHContainerOperations from Frontend
-  # to Serialization, but this broke builds that set
-  # -DBUILD_SHARED_LIBS=on.  Revision [2] is a followup that works
-  # around the issue by adding an explicit dependency on Serialization
-  # wherever there was a dependency on Frontend.  Since we depend on
-  # Frontend, we need an explicit dependency on Serialization too.
-  # [1] https://llvm.org/viewvc/llvm-project?view=revision&revision=348907
-  # [2] https://llvm.org/viewvc/llvm-project?view=revision&revision=348915
-  clangSerialization
-  )
+# If only clang-cpp is available, we take that.
+if (TARGET clang-cpp AND NOT TARGET clangBasic)
+  target_link_libraries(include-what-you-use PRIVATE clang-cpp)
+else()
+  target_link_libraries(include-what-you-use
+    PRIVATE
+    clangBasic
+    clangLex
+    clangAST
+    clangSema
+    clangFrontend
+    clangDriver
+
+    # Revision [1] in clang moved PCHContainerOperations from Frontend
+    # to Serialization, but this broke builds that set
+    # -DBUILD_SHARED_LIBS=on.  Revision [2] is a followup that works
+    # around the issue by adding an explicit dependency on Serialization
+    # wherever there was a dependency on Frontend.  Since we depend on
+    # Frontend, we need an explicit dependency on Serialization too.
+    # [1] https://llvm.org/viewvc/llvm-project?view=revision&revision=348907
+    # [2] https://llvm.org/viewvc/llvm-project?view=revision&revision=348915
+    clangSerialization
+    )
+endif()
 
 # Platform dependencies.
 if (WIN32)
-- 
2.23.0