Revert "[cmake] Do not set CMAKE_INCLUDE_CURRENT_DIR."

This reverts commit 3168df8.

Author: gottesmm

CMakeLists.txt

@@ -393,6 +393,17 @@ if("${SWIFT_NATIVE_SWIFT_TOOLS_PATH}" STREQUAL "")
   set(SWIFT_NATIVE_SWIFT_TOOLS_PATH "${SWIFT_RUNTIME_OUTPUT_INTDIR}")
 endif()
 
+# This setting causes all CMakeLists.txt to automatically have
+# ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CURRENT_SOURCE_DIR} as an
+# include_directories path. This is done for developer
+# convenience. Additionally, LLVM/Clang build with this option enabled, so we
+# should match them unless it is removed from LLVM/Clang as well.
+#
+# *NOTE* Even though these directories are added to the include path for a
+# specific CMakeLists.txt, these include paths are not propagated down to
+# subdirectories.
+set(CMAKE_INCLUDE_CURRENT_DIR ON)
+
 # We'll need this once we have generated headers
 include_directories(BEFORE
   ${CMAKE_CURRENT_BINARY_DIR}/include

lib/ClangImporter/CMakeLists.txt

@@ -23,7 +23,5 @@ add_swift_library(swiftClangImporter STATIC
     swiftParse
 )
 
-# Include the current binary dir since we rely on gybed files.
-include_directories(${CMAKE_CURRENT_BINARY_DIR})
 
 add_dependencies(swiftClangImporter "${generated_include_targets}")

tools/SourceKit/tools/sourcekitd-test/CMakeLists.txt

@@ -1,9 +1,6 @@
 set(LLVM_TARGET_DEFINITIONS Options.td)
 swift_tablegen(Options.inc -gen-opt-parser-defs)
 swift_add_public_tablegen_target(sourcekitdTestOptionsTableGen)
-# Add this directories binary directory to the include list to make sure that we
-# can properly include Options.inc.
-include_directories(${CMAKE_CURRENT_BINARY_DIR})
 
 if(SWIFT_SOURCEKIT_USE_INPROC_LIBRARY)
   set(SOURCEKITD_TEST_DEPEND sourcekitdInProc)