19 files changed, 84 insertions, 52 deletions
diff --git a/Auxiliary/vim/syntax/cmake.vim b/Auxiliary/vim/syntax/cmake.vim
index 1f19cb7..aca7c41 100644
--- a/Auxiliary/vim/syntax/cmake.vim
+++ b/Auxiliary/vim/syntax/cmake.vim
@@ -320,7 +320,7 @@ syn keyword cmakeKWremove
             \ contained
 
 syn keyword cmakeKWseparate_arguments
-            \ MSDN UNIX_COMMAND VARIABLE WINDOWS WINDOWS_COMMAND _COMMAND
+            \ MSDN NATIVE_COMMAND UNIX_COMMAND VARIABLE WINDOWS WINDOWS_COMMAND _COMMAND
             \ contained
 
 syn keyword cmakeKWset
diff --git a/Help/command/separate_arguments.rst b/Help/command/separate_arguments.rst
index 1fd3cd1..47982a5 100644
--- a/Help/command/separate_arguments.rst
+++ b/Help/command/separate_arguments.rst
@@ -5,9 +5,9 @@ Parse space-separated arguments into a semicolon-separated list.
 
 ::
 
-  separate_arguments(<var> <UNIX|WINDOWS>_COMMAND "<args>")
+  separate_arguments(<var> <NATIVE|UNIX|WINDOWS>_COMMAND "<args>")
 
-Parses a unix- or windows-style command-line string "<args>" and
+Parses a UNIX- or Windows-style command-line string "<args>" and
 stores a semicolon-separated list of the arguments in ``<var>``.  The
 entire command line must be given in one "<args>" argument.
 
@@ -16,12 +16,15 @@ recognizes both single-quote and double-quote pairs.  A backslash
 escapes the next literal character (``\"`` is ``"``); there are no special
 escapes (``\n`` is just ``n``).
 
-The ``WINDOWS_COMMAND`` mode parses a windows command-line using the same
+The ``WINDOWS_COMMAND`` mode parses a Windows command-line using the same
 syntax the runtime library uses to construct argv at startup.  It
 separates arguments by whitespace that is not double-quoted.
 Backslashes are literal unless they precede double-quotes.  See the
 MSDN article `Parsing C Command-Line Arguments`_ for details.
 
+The ``NATIVE_COMMAND`` mode parses a Windows command-line if the host
+system is Windows, and a UNIX command-line otherwise.
+
 .. _`Parsing C Command-Line Arguments`: https://msdn.microsoft.com/library/a1y7w461.aspx
 
 ::
diff --git a/Help/release/dev/separgs-native.rst b/Help/release/dev/separgs-native.rst
new file mode 100644
index 0000000..943f08e
--- /dev/null
+++ b/Help/release/dev/separgs-native.rst
@@ -0,0 +1,5 @@
+separgs-native
+-------------------
+
+* A ``NATIVE_COMMAND`` mode was added to :command:`separate_arguments`
+  performing argument separation depening on the host operating system.
diff --git a/Modules/CMakeParseImplicitLinkInfo.cmake b/Modules/CMakeParseImplicitLinkInfo.cmake
index 3273443..ad3c00f 100644
--- a/Modules/CMakeParseImplicitLinkInfo.cmake
+++ b/Modules/CMakeParseImplicitLinkInfo.cmake
@@ -38,11 +38,7 @@ function(CMAKE_PARSE_IMPLICIT_LINK_INFO text lib_var dir_var fwk_var log_var obj
           set(line "${xline}")
         endif()
       endif()
-      if(UNIX)
-        separate_arguments(args UNIX_COMMAND "${line}")
-      else()
-        separate_arguments(args WINDOWS_COMMAND "${line}")
-      endif()
+      separate_arguments(args NATIVE_COMMAND "${line}")
       list(GET args 0 cmd)
     endif()
     set(is_msvc 0)
diff --git a/Modules/FindHDF5.cmake b/Modules/FindHDF5.cmake
index 1e2ea69..5962c5b 100644
--- a/Modules/FindHDF5.cmake
+++ b/Modules/FindHDF5.cmake
@@ -354,11 +354,7 @@ macro( _HDF5_parse_compile_line
     libraries
     libraries_hl)
 
-  if(UNIX)
-    separate_arguments(_HDF5_COMPILE_ARGS UNIX_COMMAND "${${compile_line_var}}")
-  else()
-    separate_arguments(_HDF5_COMPILE_ARGS WINDOWS_COMMAND "${${compile_line_var}}")
-  endif()
+  separate_arguments(_HDF5_COMPILE_ARGS NATIVE_COMMAND "${${compile_line_var}}")
 
   foreach(arg IN LISTS _HDF5_COMPILE_ARGS)
     if("${arg}" MATCHES "^-I(.*)$")
diff --git a/Modules/FindMPI.cmake b/Modules/FindMPI.cmake
index fab53cb..37f3255 100644
--- a/Modules/FindMPI.cmake
+++ b/Modules/FindMPI.cmake
@@ -645,8 +645,7 @@ foreach (lang C CXX Fortran)
         add_library(MPI::MPI_${lang} INTERFACE IMPORTED)
       endif()
       if(MPI_${lang}_COMPILE_FLAGS)
-        set(_MPI_${lang}_COMPILE_OPTIONS "${MPI_${lang}_COMPILE_FLAGS}")
-        separate_arguments(_MPI_${lang}_COMPILE_OPTIONS)
+        separate_arguments(_MPI_${lang}_COMPILE_OPTIONS NATIVE_COMMAND "${MPI_${lang}_COMPILE_FLAGS}")
         set_property(TARGET MPI::MPI_${lang} PROPERTY
           INTERFACE_COMPILE_OPTIONS "${_MPI_${lang}_COMPILE_OPTIONS}")
       endif()
diff --git a/Modules/FindOpenMP.cmake b/Modules/FindOpenMP.cmake
index 8c1b018..e7d9d5f 100644
--- a/Modules/FindOpenMP.cmake
+++ b/Modules/FindOpenMP.cmake
@@ -411,11 +411,7 @@ foreach(LANG IN ITEMS C CXX Fortran)
         add_library(OpenMP::OpenMP_${LANG} INTERFACE IMPORTED)
       endif()
       if(OpenMP_${LANG}_FLAGS)
-        if(CMAKE_HOST_WIN32)
-          separate_arguments(_OpenMP_${LANG}_OPTIONS WINDOWS_COMMAND "${OpenMP_${LANG}_FLAGS}")
-        else()
-          separate_arguments(_OpenMP_${LANG}_OPTIONS UNIX_COMMAND "${OpenMP_${LANG}_FLAGS}")
-        endif()
+        separate_arguments(_OpenMP_${LANG}_OPTIONS NATIVE_COMMAND "${OpenMP_${LANG}_FLAGS}")
         set_property(TARGET OpenMP::OpenMP_${LANG} PROPERTY
           INTERFACE_COMPILE_OPTIONS "${_OpenMP_${LANG}_OPTIONS}")
         unset(_OpenMP_${LANG}_OPTIONS)
diff --git a/Source/cmSeparateArgumentsCommand.cxx b/Source/cmSeparateArgumentsCommand.cxx
index b27d227..7b222a0 100644
--- a/Source/cmSeparateArgumentsCommand.cxx
+++ b/Source/cmSeparateArgumentsCommand.cxx
@@ -40,6 +40,13 @@ bool cmSeparateArgumentsCommand::InitialPass(
     if (doing == DoingVariable) {
       var = args[i];
       doing = DoingMode;
+    } else if (doing == DoingMode && args[i] == "NATIVE_COMMAND") {
+#ifdef _WIN32
+      mode = ModeWindows;
+#else
+      mode = ModeUnix;
+#endif
+      doing = DoingCommand;
     } else if (doing == DoingMode && args[i] == "UNIX_COMMAND") {
       mode = ModeUnix;
       doing = DoingCommand;
diff --git a/Tests/CMakeTests/CMakeLists.txt b/Tests/CMakeTests/CMakeLists.txt
index 1cca35d..1619081 100644
--- a/Tests/CMakeTests/CMakeLists.txt
+++ b/Tests/CMakeTests/CMakeLists.txt
@@ -19,7 +19,6 @@ AddCMakeTest(GetFilenameComponentRealpath "")
 AddCMakeTest(Version "")
 AddCMakeTest(Message "")
 AddCMakeTest(File "")
-AddCMakeTest(SeparateArguments "")
 AddCMakeTest(ImplicitLinkInfo "")
 AddCMakeTest(ModuleNotices "")
 AddCMakeTest(GetProperty "")
diff --git a/Tests/CMakeTests/SeparateArgumentsTest.cmake.in b/Tests/CMakeTests/SeparateArgumentsTest.cmake.in
deleted file mode 100644
index 48964b8..0000000
--- a/Tests/CMakeTests/SeparateArgumentsTest.cmake.in
+++ /dev/null
@@ -1,25 +0,0 @@
-set(old_out "a b  c")
-separate_arguments(old_out)
-set(old_exp "a;b;;c")
-
-set(unix_cmd "a \"b c\" 'd e' \";\" \\ \\'\\\" '\\'' \"\\\"\"")
-set(unix_exp "a;b c;d e;\;; '\";';\"")
-separate_arguments(unix_out UNIX_COMMAND "${unix_cmd}")
-
-set(windows_cmd "a \"b c\" 'd e' \";\" \\ \"c:\\windows\\path\\\\\" \\\"")
-set(windows_exp "a;b c;'d;e';\;;\\;c:\\windows\\path\\;\"")
-separate_arguments(windows_out WINDOWS_COMMAND "${windows_cmd}")
-
-foreach(mode old unix windows)
-  if(NOT "${${mode}_out}" STREQUAL "${${mode}_exp}")
-    message(FATAL_ERROR "separate_arguments ${mode}-style failed.  "
-      "Expected\n  [${${mode}_exp}]\nbut got\n  [${${mode}_out}]\n")
-  endif()
-endforeach()
-
-set(nothing)
-separate_arguments(nothing)
-if(DEFINED nothing)
-  message(FATAL_ERROR "separate_arguments null-case failed: "
-    "nothing=[${nothing}]")
-endif()
diff --git a/Tests/FindOpenMP/Test/CMakeLists.txt b/Tests/FindOpenMP/Test/CMakeLists.txt
index 4ba0e5c..6313ef6 100644
--- a/Tests/FindOpenMP/Test/CMakeLists.txt
+++ b/Tests/FindOpenMP/Test/CMakeLists.txt
@@ -39,11 +39,7 @@ foreach(c C CXX Fortran)
   add_test(NAME test_tgt_${c} COMMAND test_tgt_${c})
 
   add_executable(test_var_${c} ${OpenMPTEST_SOURCE_FILE})
-  if(CMAKE_HOST_WIN32)
-    separate_arguments(_OpenMP_${c}_OPTIONS WINDOWS_COMMAND "${OpenMP_${c}_FLAGS}")
-  else()
-    separate_arguments(_OpenMP_${c}_OPTIONS UNIX_COMMAND "${OpenMP_${c}_FLAGS}")
-  endif()
+  separate_arguments(_OpenMP_${c}_OPTIONS NATIVE_COMMAND "${OpenMP_${c}_FLAGS}")
   target_compile_options(test_var_${c} PRIVATE "${_OpenMP_${c}_OPTIONS}")
   target_link_libraries(test_var_${c} PRIVATE "${OpenMP_${c}_FLAGS}")
   set_property(TARGET test_var_${c} PROPERTY LINKER_LANGUAGE ${c})
diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index cf778b6..75d4e29 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -217,6 +217,7 @@ add_RunCMake_test(list)
 add_RunCMake_test(message)
 add_RunCMake_test(project -DCMake_TEST_RESOURCES=${CMake_TEST_RESOURCES})
 add_RunCMake_test(return)
+add_RunCMake_test(separate_arguments)
 add_RunCMake_test(set_property)
 add_RunCMake_test(string)
 foreach(var
diff --git a/Tests/RunCMake/separate_arguments/CMakeLists.txt b/Tests/RunCMake/separate_arguments/CMakeLists.txt
new file mode 100644
index 0000000..2897109
--- /dev/null
+++ b/Tests/RunCMake/separate_arguments/CMakeLists.txt
@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.0)
+project(${RunCMake_TEST} NONE)
+include(${RunCMake_TEST}.cmake)
diff --git a/Tests/RunCMake/separate_arguments/EmptyCommand.cmake b/Tests/RunCMake/separate_arguments/EmptyCommand.cmake
new file mode 100644
index 0000000..895b6ac
--- /dev/null
+++ b/Tests/RunCMake/separate_arguments/EmptyCommand.cmake
@@ -0,0 +1,6 @@
+set(nothing)
+separate_arguments(nothing)
+if(DEFINED nothing)
+  message(FATAL_ERROR "separate_arguments null-case failed: "
+    "nothing=[${nothing}]")
+endif()
diff --git a/Tests/RunCMake/separate_arguments/NativeCommand.cmake b/Tests/RunCMake/separate_arguments/NativeCommand.cmake
new file mode 100644
index 0000000..1cb009e
--- /dev/null
+++ b/Tests/RunCMake/separate_arguments/NativeCommand.cmake
@@ -0,0 +1,19 @@
+set(unix_cmd "a \"b c\" 'd e' \";\" \\ \\'\\\" '\\'' \"\\\"\"")
+set(unix_exp "a;b c;d e;\;; '\";';\"")
+
+set(windows_cmd "a \"b c\" 'd e' \";\" \\ \"c:\\windows\\path\\\\\" \\\"")
+set(windows_exp "a;b c;'d;e';\;;\\;c:\\windows\\path\\;\"")
+
+if(CMAKE_HOST_WIN32)
+  set(native_cmd "${windows_cmd}")
+  set(native_exp "${windows_exp}")
+else()
+  set(native_cmd "${unix_cmd}")
+  set(native_exp "${unix_exp}")
+endif()
+separate_arguments(native_out NATIVE_COMMAND "${native_cmd}")
+
+if(NOT "${native_out}" STREQUAL "${native_exp}")
+  message(FATAL_ERROR "separate_arguments native-style failed.  "
+    "Expected\n  [${native_exp}]\nbut got\n  [${native_out}]\n")
+endif()
diff --git a/Tests/RunCMake/separate_arguments/PlainCommand.cmake b/Tests/RunCMake/separate_arguments/PlainCommand.cmake
new file mode 100644
index 0000000..311a993
--- /dev/null
+++ b/Tests/RunCMake/separate_arguments/PlainCommand.cmake
@@ -0,0 +1,8 @@
+set(old_out "a b  c")
+separate_arguments(old_out)
+set(old_exp "a;b;;c")
+
+if(NOT "${old_out}" STREQUAL "${old_exp}")
+  message(FATAL_ERROR "separate_arguments old-style failed.  "
+    "Expected\n  [${old_exp}]\nbut got\n  [${old_out}]\n")
+endif()
diff --git a/Tests/RunCMake/separate_arguments/RunCMakeTest.cmake b/Tests/RunCMake/separate_arguments/RunCMakeTest.cmake
new file mode 100644
index 0000000..07951bb
--- /dev/null
+++ b/Tests/RunCMake/separate_arguments/RunCMakeTest.cmake
@@ -0,0 +1,7 @@
+include(RunCMake)
+
+run_cmake(EmptyCommand)
+run_cmake(PlainCommand)
+run_cmake(UnixCommand)
+run_cmake(WindowsCommand)
+run_cmake(NativeCommand)
diff --git a/Tests/RunCMake/separate_arguments/UnixCommand.cmake b/Tests/RunCMake/separate_arguments/UnixCommand.cmake
new file mode 100644
index 0000000..0b5767a
--- /dev/null
+++ b/Tests/RunCMake/separate_arguments/UnixCommand.cmake
@@ -0,0 +1,8 @@
+set(unix_cmd "a \"b c\" 'd e' \";\" \\ \\'\\\" '\\'' \"\\\"\"")
+set(unix_exp "a;b c;d e;\;; '\";';\"")
+separate_arguments(unix_out UNIX_COMMAND "${unix_cmd}")
+
+if(NOT "${unix_out}" STREQUAL "${unix_exp}")
+  message(FATAL_ERROR "separate_arguments unix-style failed.  "
+    "Expected\n  [${unix_exp}]\nbut got\n  [${unix_out}]\n")
+endif()
diff --git a/Tests/RunCMake/separate_arguments/WindowsCommand.cmake b/Tests/RunCMake/separate_arguments/WindowsCommand.cmake
new file mode 100644
index 0000000..86aa14a
--- /dev/null
+++ b/Tests/RunCMake/separate_arguments/WindowsCommand.cmake
@@ -0,0 +1,8 @@
+set(windows_cmd "a \"b c\" 'd e' \";\" \\ \"c:\\windows\\path\\\\\" \\\"")
+set(windows_exp "a;b c;'d;e';\;;\\;c:\\windows\\path\\;\"")
+separate_arguments(windows_out WINDOWS_COMMAND "${windows_cmd}")
+
+if(NOT "${windows_out}" STREQUAL "${windows_exp}")
+  message(FATAL_ERROR "separate_arguments windows-style failed.  "
+    "Expected\n  [${windows_exp}]\nbut got\n  [${windows_out}]\n")
+endif()