Add dependencies where targets depend on inclusions from unspecified targets.

A follow-up PR adds a flag to control an inline namespace that allows
symbols in libDemangling to be distinguished between the runtime and
the compiler. These dependencies ensure that the flag is plumbed
through for inclusions of Demangling headers that aren't already
covered by existing `target_link_libraries`.

lib/RemoteAST/CMakeLists.txt

@@ -15,6 +15,8 @@ add_swift_host_library(swiftRemoteAST STATIC
   RemoteAST.cpp
   InProcessMemoryReader.cpp
   ${REMOTE_LIB_HEADERS})
+target_link_libraries(swiftRemoteAST PUBLIC
+  swiftDemangling)
 target_link_libraries(swiftRemoteAST PRIVATE
   swiftIRGen
   swiftSema)