Expand absolute path later in get_cpm.cmake (#397)

* Expand absolute path later in get_cpm.cmake

Supports expanding tildes in the environment.

* Apply cmake-format to get_cpm.cmake

* Use .cmake-format file

Author: kisielk

cmake/get_cpm.cmake

@@ -1,15 +1,15 @@
 set(CPM_DOWNLOAD_VERSION 1.0.0-development-version)
 
 if(CPM_SOURCE_CACHE)
-  # Expand relative path. This is important if the provided path contains a tilde (~)
-  get_filename_component(CPM_SOURCE_CACHE ${CPM_SOURCE_CACHE} ABSOLUTE)
   set(CPM_DOWNLOAD_LOCATION "${CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
 elseif(DEFINED ENV{CPM_SOURCE_CACHE})
   set(CPM_DOWNLOAD_LOCATION "$ENV{CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
 else()
   set(CPM_DOWNLOAD_LOCATION "${CMAKE_BINARY_DIR}/cmake/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
 endif()
 
+# Expand relative path. This is important if the provided path contains a tilde (~)
+get_filename_component(CPM_DOWNLOAD_LOCATION ${CPM_DOWNLOAD_LOCATION} ABSOLUTE)
 if(NOT (EXISTS ${CPM_DOWNLOAD_LOCATION}))
   message(STATUS "Downloading CPM.cmake to ${CPM_DOWNLOAD_LOCATION}")
   file(DOWNLOAD