heavily rework lua discovery and linking, needs testing but it's more similar to what we do for other libraries now
macro(find_package_or_fail _PKG_NAME)
find_package(${_PKG_NAME})
string(TOUPPER ${_PKG_NAME} _PKG_NAME_UP)
if(NOT ${_PKG_NAME_UP}_FOUND)
message(SEND_ERROR "Missing ${_PKG_NAME}! Please install it and rerun cmake.")
endif(NOT ${_PKG_NAME_UP}_FOUND)
endmacro(find_package_or_fail _PKG_NAME)
macro(find_package_or_disable _PKG_NAME _VAR_NAME)
find_package(${_PKG_NAME})
string(TOUPPER ${_PKG_NAME} _PKG_NAME_UP)
if(NOT ${_PKG_NAME_UP}_FOUND)
message(SEND_ERROR "Missing ${_PKG_NAME}! Rerun cmake with -D${_VAR_NAME}=1 to build without it.")
endif(NOT ${_PKG_NAME_UP}_FOUND)
endmacro(find_package_or_disable _PKG_NAME _VAR_NAME)
macro(find_package_or_disable_msg _PKG_NAME _VAR_NAME _MSG)
if(NOT ${_VAR_NAME})
find_package_or_disable(${_PKG_NAME} ${_VAR_NAME})
else(NOT ${_VAR_NAME})
message(STATUS "${_PKG_NAME} disabled. ${_MSG}")
string(TOUPPER ${_PKG_NAME} _PKG_NAME_UP)
set(${_PKG_NAME_UP}_FOUND false)
endif(NOT ${_VAR_NAME})
endmacro(find_package_or_disable_msg _PKG_NAME _VAR_NAME _MSG)
#TODO: find_package_or_bundle