Kpathsea: A library for path searching

Here are some common installation scenarios:

Including X support in Metafont. This is disabled by default, since many sites have no use for it, and it's a leading cause of configuration problems.
```
configure --with-x-toolkit
```
Putting the binaries, TeX files, GNU info files, etc. into a single TeX hierarchy, say texmf, requires overriding defaults in both configure and make:
```
configure --prefix=texmf --datadir=texmf
make texmf=texmf
```
You can compile on multiple architectures simultaneously either by building symbolic link trees with the lndir script from the X11 distribution, or with the `--srcdir' option:
```
configure --srcdir=srcdir
```
If you are installing binaries for multiple architectures into a single hierarchy, you will probably want to override the default `bin' and `lib' directories, something like this:
```
configure --prefix=texmf --datadir=texmf \
  --bindir=texmf/arch/bin --libdir=texmf/arch/lib
make texmf=texmf
```
(Unless you make provisions for architecture-specific files in other ways, e.g., with Depot or an automounter.)
To compile with optimization (to compile without debugging, remove the `-g'):
```
env CFLAGS="-g -O" sh configure ...
```
For a potential problem if you optimize, see section TeX or Metafont failing.