issue-461: Fix to malloc_extension.h so that it builds with -std=gnu++98
issue-461: Fix to malloc_extension.h so that it builds with -std=gnu++98

git-svn-id: 005a797486ed258bc647c92414185dac8898a8a0@190 6b5cf1ce-ec42-a296-1ba9-69fdba395a50

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