Aarch64 platforms need their config.guess scripts updated. This macro does it...

Aarch64 platforms need their config.guess scripts updated. This macro does it for every external, after untarring stage. The problem is it does it for all platforms. We're not sure how to choose aarch64 here as the LCG_TARGET_PLATFORM isn't defined yet

cmake/modules/ExternalProject.cmake

@@ -610,6 +610,11 @@ if(NOT rv EQUAL 0)
   message(FATAL_ERROR \"error: extract of '\${filename}' failed\")
 endif()
 
+# Update the config.guess files.
+#
+message(STATUS \"Updating the config.guess file...\")
+execute_process(COMMAND ${CMAKE_SOURCE_DIR}/cmake/modules/update.ConfigGuess)
+
 # Analyze what came out of the tar file:
 #
 message(STATUS \"extracting... [analysis]\")

cmake/modules/update.ConfigGuess

+#!/bin/bash
+for i in $(find -name config.guess); do
+	if [ -n "$i" ]; then
+		echo "Found: $i"
+		wget -O $i 'http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess;hb=HEAD'
+	fi
+done