pgsql: llvmjit: Work around bug in LLVM 3.9 causing crashes after 72559
llvmjit: Work around bug in LLVM 3.9 causing crashes after 72559438f92.
Unfortunately in LLVM 3.9 LLVMGetAttributeCountAtIndex(func, index)
crashes when called with an index that has 0 attributes. Since there's
no way to work around this in the C API, add a small C++ wrapper doing
The only reason this didn't fail before 72559438f92 is that there
always are function attributes...