The Modules/ThirdParty/DoubleConversion/src/double-conversion
subdirectory contains a reduced distribution of the Google
double-conversion source tree with just the library source.

Modules/ThirdParty/DoubleConversion/src/UpdateDoubleConversionFromGoogle.sh
describes the procedure to  merge in any new changes in the upstream
Google repository.

Note: After the upstream double-conversion code has been merged and
tested, and BEFORE using git gerrit-push to push the topic to the
Kitware Gerrit, use the procedure documented at the bottom of the
Update script to recover the upstream merge hash and put it in the
update script.

Search for EDIT THIS SCRIPT in UpdateDoubleConversionFromGoogle.sh to
find the point to change the hash number.
