add wrapmemcpy=yes flag to wrap memcpy(3)

for glibc backward compatibility
remove unused variable
simplify Makefile
Merge pull request #266 from gordon/memcpy

add wrapmemcpy=yes flag to wrap memcpy(3)
do not copy binary twice for dist target

strip binary for install target
Merge pull request #267 from gordon/makefile

do not copy binary twice for dist target