Prefer compound statements to lambdas

Compound statements produce better error messages.
Simplify DXX_VALPTRIDX_STATIC_CHECK
Reduce newdemo_read_frame_information segnum scope

At broad scope, gcc complains about potential uninitialized usage.
Improve __builtin_constant_p test

Discourage compiler from inlining due to -finline-functions-called-once.
Otherwise, -O2 -fno-inline will inline the sconf test, but not inline
real usage.
Rewrite DXX_PHYSFS_CHECK_* to avoid if
Propagate loop variable to silence gcc 4.6 warning

Suppress warning about changed variable scope under new ISO C++ rules.
Optimistically reorder tests

Run tests last-to-first to detect success immediately.  Run the lesser
tests next, so that build logs show what the compiler can do.
Fix mismatched new/free
Fix tests with -Wunused-parameter
Allow constructing valptridx_t(index_type) from ~0