Error with SoftHSM installation prefix

./configure --program-prefix=/opt/softhsm --with-botan=/opt/botan

make[3]: Nothing to be done for `install-data-am'.
make[3]: Leaving directory `/home/username/install/softhsm-1.1.4/src/lib'
make[2]: Leaving directory `/home/username/install/softhsm-1.1.4/src/lib'
Making install in bin
make[2]: Entering directory `/home/username/install/softhsm-1.1.4/src/bin'
make[3]: Entering directory `/home/username/install/softhsm-1.1.4/src/bin'
test -z "/usr/local/bin" || /bin/mkdir -p "/usr/local/bin"
  /bin/sh ../../libtool   --mode=install /usr/bin/install -c 'softhsm' '/usr/local/bin//opt/softhsmsofthsm'
libtool: install: /usr/bin/install -c softhsm /usr/local/bin//opt/softhsmsofthsm
/usr/bin/install: cannot create regular file `/usr/local/bin//opt/softhsmsofthsm': No such file or directory
make[3]: *** [install-binPROGRAMS] Error 1
make[3]: Leaving directory `/home/username/install/softhsm-1.1.4/src/bin'
make[2]: *** [install-am] Error 2
make[2]: Leaving directory `/home/username/install/softhsm-1.1.4/src/bin'
make[1]: *** [install-recursive] Error 1
make[1]: Leaving directory `/home/username/install/softhsm-1.1.4/src'
make: *** [install-recursive] Error 1