build: add a dependency on the just built clang (NFC)

When building in a unified build and building the host tools with a
non-clang compiler, we switch compilers.  In such a case, we need to
actually add an explicit dependency on the new compiler.

Author: compnerd

tools/SourceKit/cmake/modules/AddSwiftSourceKit.cmake

@@ -132,6 +132,9 @@ macro(add_sourcekit_library name)
     set(libkind)
   endif()
   add_library(${name} ${libkind} ${srcs})
+  if(NOT SWIFT_BUILT_STANDALONE AND NOT CMAKE_C_COMPILER_ID MATCHES Clang)
+    add_dependencies(${name} clang)
+  endif()
   llvm_update_compile_flags(${name})
 
   set_output_directory(${name}
@@ -228,6 +231,9 @@ macro(add_sourcekit_executable name)
   else()
     add_executable(${name} ${SOURCEKITEXE_UNPARSED_ARGUMENTS})
   endif()
+  if(NOT SWIFT_BUILT_STANDALONE AND NOT CMAKE_C_COMPILER_ID MATCHES Clang)
+    add_dependencies(${name} clang)
+  endif()
   llvm_update_compile_flags(${name})
   set_output_directory(${name}
       BINARY_DIR ${SOURCEKIT_RUNTIME_OUTPUT_INTDIR}

tools/libSwiftSyntaxParser/CMakeLists.txt

@@ -10,6 +10,9 @@ set(LLVM_EXPORTED_SYMBOL_FILE
 add_swift_host_library(libSwiftSyntaxParser SHARED
   c-include-check.c
   libSwiftSyntaxParser.cpp)
+if(NOT SWIFT_BUILT_STANDALONE AND NOT CMAKE_C_COMPILER_ID MATCHES Clang)
+  add_dependencies(libSwiftSyntaxParser clang)
+endif()
 target_link_libraries(libSwiftSyntaxParser PRIVATE
   swiftParse)
 set_target_properties(libSwiftSyntaxParser

tools/swift-syntax-parser-test/CMakeLists.txt

@@ -7,6 +7,9 @@ add_swift_host_tool(swift-syntax-parser-test
     Support
   SWIFT_COMPONENT tools
 )
+if(NOT SWIFT_BUILT_STANDALONE AND NOT CMAKE_C_COMPILER_ID MATCHES Clang)
+  add_dependencies(swift-syntax-parser-test clang)
+endif()
 target_link_libraries(swift-syntax-parser-test
   PRIVATE
     libSwiftSyntaxParser

unittests/SyntaxParser/CMakeLists.txt

@@ -4,6 +4,9 @@ swift_swap_compiler_if_needed("SyntaxParserUnitTests")
 add_swift_unittest(SwiftSyntaxParserTests
   SyntaxParserTests.cpp
 )
+if(NOT SWIFT_BUILT_STANDALONE AND NOT CMAKE_C_COMPILER_ID STREQUAL Clang)
+  add_dependencies(SwiftSyntaxParserTests clang)
+endif()
 
 target_link_libraries(SwiftSyntaxParserTests
   PRIVATE