This fixes a few build issues on Solaris 5.10 with gcc as well as native compiler.
solaris: define u_int/u_int32_t in all compilers
The solarisfixes.h defines for u_int/u_int32_t were only defined when __GNUC__. They are also needed to build using the Oracle Studio C compiler.
solaris: avoid HAVE_BACKTRACE when __SunOS_5_10
The backtrace(3) function was only added in Solaris 11. The __SunOS_5_10 define is provided by the Oracle Studio compiler. Other compilers can simply -D__SunOS_5_10 if they are running on Solaris 10 and hit this issue.
solaris: add unistd.h for ioctl()