Allow usage of mirrors for all dependencies

cmake/VarsFromFile.cmake

@@ -0,0 +1,13 @@
+function(VarsFromFile filename)
+    file(STRINGS ${filename} ConfigContents)
+    foreach(NameAndValue ${ConfigContents})
+        # Strip leading spaces
+        string(REGEX REPLACE "^[ ]+" "" NameAndValue ${NameAndValue})
+        # Find variable name
+        string(REGEX MATCH "^[^=]+" Name ${NameAndValue})
+        # Find the value
+        string(REPLACE "${Name}=" "" Value ${NameAndValue})
+        # Set the variable
+        set(${Name} "${Value}" PARENT_SCOPE)
+    endforeach()
+endfunction(VarsFromFile)