Include the full version number in the directory paths installed.
Change the version string so that it does not break 'make', and so that it has no '/' (it would be a hell if installed directories would mirror the SVN branches... :-/ )
Do not use implicit rules for the Makefile.
Simplify and enc=hance the --local test to refuse (un)installing.
Double-quotes variables, they are based on user input.
Eye-candy in the 'compile' and install messages.

/trunk/configure | 26 14 12 0 ++++++++++---------
/trunk/Makefile.in | 83 45 38 0 +++++++++++++++++++++++++++++++++---------------------------
2 files changed, 59 insertions(+), 50 deletions(-)

 # Compute x86_64-specific values

 CT_DoArchValues() {

     # The architecture part of the tuple:

     CT_TARGET_ARCH="${CT_ARCH}"

 }