Fix SIGBUS on Solaris.
Fix Warning about %o expecting unsigned int.
file_writer_test was refactored.

The reason is that previously we were redefining libc's fwrite() to
change the output location of WriterWrite(). However, on Solaris 9
fwrite() is also used in our printf() replacement which is called for
other reasons in the tests, so random crashes/behaviour was happening.

The test is now including the writer.c source file directly, which
overrides fwrite() only if #ifdef CFENGINE_TEST.
On Solaris uptime was wrong, fix it to read the proper kstat statistic.
Added two ways to compute uptime on UNIX.

Tested on Linux and Solaris 9.
Fix typo, it existed there a long time causing configure test to always fail.
Fix dependencies for sysinfo_test.
map_test is overly slow on old platforms, speedup by avoid calling memcpy a million times.
Print uptime in sysinfo_test so that it can be verified visually.
Convert sprintf calls to snprintf.
Clean up whitespace mess in sysinfo.c.