[lldb] [debugserver] Simplify handling of arch specific files

[mstorsjo]

Summary

There are no duplicates among the include files, and all the
source files are wrapped in architecture ifdefs, so there's no harm
in including all of them, always.

This fixes builds if TARGET_TRIPLE is set to something else than the
build architecture.

This also allows building for multiple architectures at once by
setting CMAKE_OSX_ARCHITECTURES.

[JDevlieghere]

Sounds reasonable, with the ifdefs in place I can't think of any reason this would break. LGTM.

lldb/tools/debugserver/source/MacOSX/CMakeLists.txt

-# The debugserver build needs to conditionally include files depending on the
-# target architecture.
-#
-# Switch on the architecture specified by TARGET_TRIPLE, as
-# the llvm and swift build systems use this variable to identify the
-# target (through LLVM_HOST_TRIPLE).
-#
-# It would be possible to switch on CMAKE_OSX_ARCHITECTURES, but the swift
-# build does not provide it, preferring instead to pass arch-specific
-# CFLAGS etc explicitly. Switching on LLVM_HOST_TRIPLE is also an option,
-# but it breaks down when cross-compiling.
-
-if(TARGET_TRIPLE)
-  string(REGEX MATCH "^[^-]*" LLDB_DEBUGSERVER_ARCH ${TARGET_TRIPLE})
-else()
-  set(LLDB_DEBUGSERVER_ARCH ${CMAKE_OSX_ARCHITECTURES})
-endif()
-
-if("${LLDB_DEBUGSERVER_ARCH}" MATCHES ".*arm.*")
-  list(APPEND SOURCES arm/DNBArchImpl.cpp arm64/DNBArchImplARM64.cpp)
-  include_directories(${CURRENT_SOURCE_DIR}/arm ${CURRENT_SOURCE_DIR}/arm64)
-endif()
 
-if(NOT LLDB_DEBUGSERVER_ARCH OR "${LLDB_DEBUGSERVER_ARCH}" MATCHES ".*86.*")
-  list(APPEND SOURCES i386/DNBArchImplI386.cpp x86_64/DNBArchImplX86_64.cpp)
-  include_directories(${CURRENT_SOURCE_DIR}/i386 ${CURRENT_SOURCE_DIR}/x86_64)
-endif()
 
 include_directories(..)
 
 include_directories(${LLDB_SOURCE_DIR}/tools/debugserver/source)
 add_library(lldbDebugserverArchSupport
   ${SOURCES}
   )
 
 set_target_properties(lldbDebugserverArchSupport PROPERTIES FOLDER "lldb libraries/debugserver")