Typedefs starting with `x' in xnu

• x0000B802 bsd/hfs/hfs_macos_defs.h:813
• xer_t EXTERNAL_HEADERS/architecture/ppc/basic_regs.h:198
• XIOParamPtr bsd/hfs/hfscommon/headers/system/MacOSStubs.h:1050
• XVolumeParamPtr bsd/hfs/hfscommon/headers/system/MacOSStubs.h:1089