Oh dear. "make install" seems to omit the target
directory from the destination path:
Making install in pixmaps
make[2]: Entering directory `/usr/src/midimountain-0.3.0/midimountain/pixmaps'
make[3]: Entering directory `/usr/src/midimountain-0.3.0/midimountain/pixmaps'
make[3]: Nothing to be done for `install-exec-am'.
/bin/sh ../../mkinstalldirs pixmaps/
mkdir pixmaps
/usr/bin/install -c -m 644 EditAdd.xpm pixmaps/EditAdd.xpm
...and then later...
make[3]: Entering directory `/usr/src/midimountain-0.3.0/midimountain'
/bin/sh ../mkinstalldirs /usr/local/bin
/usr/bin/install -c midimountain /usr/local/bin/midimountain
/bin/sh ../mkinstalldirs
/usr/bin/install -c -m 644 midimountain.conf midimountain.conf
/usr/bin/install: `midimountain.conf' and `midimountain.conf' are the same file
make[3]: *** [install-data-local] Error 1