Check for Haiku when setting LIB_NAMES for GNU ld

[korli]

Summary

Haiku uses GNU ld for linking, but is not captured in the conditional when setting LIB_NAMES. This causes a shared library with no symbols on Haiku.
This patch simply adds a check for whether the CMake system name is Haiku in addition to the existing checks.

[korli]

I haven't commit access. Could you commit the change?

llvm/trunk/tools/llvm-shlib/CMakeLists.txt

 if(LLVM_DYLIB_EXPORTED_SYMBOL_FILE)
   set(LLVM_EXPORTED_SYMBOL_FILE ${LLVM_DYLIB_EXPORTED_SYMBOL_FILE})
   add_custom_target(libLLVMExports DEPENDS ${LLVM_EXPORTED_SYMBOL_FILE})
 endif()
 
 add_llvm_library(LLVM SHARED DISABLE_LLVM_LINK_LLVM_DYLIB SONAME ${SOURCES})
 
 list(REMOVE_DUPLICATES LIB_NAMES)
-if(("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux") OR (MINGW) OR ("${CMAKE_SYSTEM_NAME}" STREQUAL "FreeBSD") OR ("${CMAKE_SYSTEM_NAME}" STREQUAL "DragonFly")) # FIXME: It should be "GNU ld for elf"
+if(("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux") OR (MINGW) OR (HAIKU) OR ("${CMAKE_SYSTEM_NAME}" STREQUAL "FreeBSD") OR ("${CMAKE_SYSTEM_NAME}" STREQUAL "DragonFly")) # FIXME: It should be "GNU ld for elf"
   configure_file(
   ${CMAKE_CURRENT_SOURCE_DIR}/simple_version_script.map.in
   ${LLVM_LIBRARY_DIR}/tools/llvm-shlib/simple_version_script.map)
 
   # GNU ld doesn't resolve symbols in the version script.
   set(LIB_NAMES -Wl,--version-script,${LLVM_LIBRARY_DIR}/tools/llvm-shlib/simple_version_script.map -Wl,--whole-archive ${LIB_NAMES} -Wl,--no-whole-archive)
 elseif("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
   set(LIB_NAMES -Wl,-all_load ${LIB_NAMES})