use system FindPython if newer

Avoid needing to keep our copy updated and only keep it as a fallback
for when system cmake is not new enough.

1 files changed, 48 insertions, 0 deletions

diff --git a/cmake/python-backport/FindPackageMessage.cmake b/cmake/python-backport/FindPackageMessage.cmake
new file mode 100644
index 00000000..0628b981
--- /dev/null
+++ b/cmake/python-backport/FindPackageMessage.cmake
@@ -0,0 +1,48 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+#[=======================================================================[.rst:
+FindPackageMessage
+------------------
+
+.. code-block:: cmake
+
+  find_package_message(<name> "message for user" "find result details")
+
+This function is intended to be used in FindXXX.cmake modules files.
+It will print a message once for each unique find result.  This is
+useful for telling the user where a package was found.  The first
+argument specifies the name (XXX) of the package.  The second argument
+specifies the message to display.  The third argument lists details
+about the find result so that if they change the message will be
+displayed again.  The macro also obeys the QUIET argument to the
+find_package command.
+
+Example:
+
+.. code-block:: cmake
+
+  if(X11_FOUND)
+    find_package_message(X11 "Found X11: ${X11_X11_LIB}"
+      "[${X11_X11_LIB}][${X11_INCLUDE_DIR}]")
+  else()
+   ...
+  endif()
+#]=======================================================================]
+
+function(find_package_message pkg msg details)
+  # Avoid printing a message repeatedly for the same find result.
+  if(NOT ${pkg}_FIND_QUIETLY)
+    string(REPLACE "\n" "" details "${details}")
+    set(DETAILS_VAR FIND_PACKAGE_MESSAGE_DETAILS_${pkg})
+    if(NOT "${details}" STREQUAL "${${DETAILS_VAR}}")
+      # The message has not yet been printed.
+      message(STATUS "${msg}")
+
+      # Save the find details in the cache to avoid printing the same
+      # message again.
+      set("${DETAILS_VAR}" "${details}"
+        CACHE INTERNAL "Details about finding ${pkg}")
+    endif()
+  endif()
+endfunction()