It's there -- kind of.
In gdal-1.1.8.tar.gz
see the following files within the tar structure:
gdal-1.1.8\html\cpl_config_h-source.html <-instructions
gdal-1.1.8\port\cpl_config.h.in
gdal-1.1.8\port\cpl_config.h.vc
gdal-1.1.8\ogr\ogrsf_frmts\dgn\readme <- more instructions
From cpl_config_h-source.html:
00001 /* port/cpl_config.h. Generated automatically by configure. */
00002 /* port/cpl_config.h.in. Generated automatically from
configure.in by autoheader. */
From gdal-1.1.8\ogr\ogrsf_frmts\dgn\readme:
Building
--------
This is a preliminary source distribution, and I have not gone to any
pains to make it easy to configure and build. To build please do the
following:
1. Update cpl_config.h to represent your platform accurately. Generally all
that matters is to #define WORDS_BIGENDIAN on big endian platforms. The
rest can likely be ignored.
[snip]
------------------------------------------------------------------
evidently it gets created in the configure process when you build
DNGLIB?