Improve the behaviour of the build system wrt depend files.
- Remove the -Y option for makedepend, so that the standard
directories are searched
- No longer pipe the multiple errors that the -Y option caused
into /dev/null -- we want to know about these failures.
- Fix up a few other misc makedepend failures.
Make sure mklib sees the definition of CC and CXX. Make mklib respect
the definitions of CC and CXX on Linux. This fixed build issues with
sunos5-gcc and build issues on GCC 2.x Linux when CC and CXX are set
to a GCC 3.x compiler.
Build fixing for FreeBSD. GNU make is installed as gmake, so make a MAKE
variable (defaults to "make") and use that. Use the MKDEP and MKDEP_OPTIONS
more. Our shell isn't bash, so change the instances of ">& /dev/null" to a more
compatible "> /dev/null 2>&1".