CONFIG_HPUX is not available for thedefaultarchitecture x86.
Result is shown for architecture parisc
default or selected kernelversion does not have config value CONFIG_HPUX.
Result is shown for kernelversion 6.5.1

Support for HP-UX binaries

configname: CONFIG_HPUX

Linux Kernel Configuration
└─>Processor type and features
└─>Support for HP-UX binaries
In linux kernel since version 2.6.12  
depends
NOT CONFIG_64BIT