The static library 'common' has no dependencies.

The following checks have been added:
- FindAWK (custom CMake module added)
- FindPerl
- FindEXPAT
- FindZLIB
- HAVE_SINCOS
- HAVE_STRINGS_H
- HAVE_SYS_TYPES_H
- HAVE_STRNCASECMP_H

The steps to generate `colortbl.h` and `ps_font_equiv.h` are the same as
in the Autotools build. DEFAULT_DPI is now set in the config.h generated
by CMake.