Ignore llgo binary/test output
Implement close() builtin
debug: don't generate nil llvm.Value{} if FileDescriptor==""

Fixes an assertion/segfault in LLVM, because we we
do an unconditional ReplaceAllUsesWith to handle
cyclic metadata references.
Implement select via libgo
Factor runtime error calls out of slice.go and attach weight metadata to the branch
Implement nil checks for field addr, index addr, load and store
Bounds checking for index addr
Fix basic block caching in condBrRuntimeError, and short circuit constant false
Fill in the type descriptor name field

The absence of this field causes the reflect library to crash.
Implement struct type descriptors
Give slices the correct type
Fix nil == []T and function compares
Implement panic(), recover() builtins