[Proj] Patch for warnings and perhaps a bug

[Thompson, David C]

Hi,

I've made some changes to PROJ.4 to get it compiling without
any warnings even setting CFLAGS="-W -Wall". I attached a
patch, but the list server wouldn't let it through. If anyone
is interested, perhaps I can break it into a couple of smaller
messages.

Most of the changes are straightforward, a few are tedious, and
one of the warnings appears to actually point to a bug. Specifically,
in src/PJ_imw_p.c it looks like the argument "double* yc" is
shadowed by a local variable below and thus never used. The patch
includes what I believe to be a fix, but it would be nice if someone
reviewed it.

The only other real problem I had was with the declaration and
initialization of "static char EMESS_H_ID[]" inside src/emess.h.
Since this header file is included multiple times it results in
EMESS_H_ID being instantiated in multiple object files. I removed
the variable since it doesn't appear to be used.

I also have some changes so that PROJ.4 can be configured with
CMake (www.cmake.org) instead of autoconf. CMake will generate
Makefiles, Xcode projects, or MSVC files. I don't have all the features
currently in the autoconf version but the basic library compiles
properly on several platforms. If anyone is interested, please let me
know.

    David