I've installed Solaris 11 x86 (in a qemu environment) from here: http://www.oracle.com/technetwork/server-storage/solaris11/downloads/index.html
I've untar'd into /opt Sun Studio 12.3 x86 for Solaris 11 from here: http://www.oracle.com/technetwork/server-storage/solarisstudio/downloads/index.html
but the compiler can't find system headers like sys/types.h or inttypes.h or anywhere which may define int32_t. The dtrace.h header for example relies on sys/types.h, and I can't find it. As if I'm missing a package or something. I've never worked with anything other than Linux (many distros, including from source), and I'm lost. What am I missing?
You just need to install the package containing these header files:
# pkg install system/header