* src/gxvalid/gxvmorx.c (gxv_morx_subtables_validate):
Conditionalize unvalidated variable `subFeatureFlags'.
(gxv_morx_chain_validate): Conditionalize unvalidated
variable `defaultFlags'.

* src/gxvalid/gxmorx0.c
(gxv_morx_subtable_type0_entry_validate):
Conditionalize unvalidated variables; `markFirst',
`dontAdvance', `markLast', `verb'.

* src/gxvalid/gxmorx1.c
(gxv_morx_subtable_type1_entry_validate): Conditionalize
unvalidated variables; `setMark', `dontAdvance'.

* src/gxvalid/gxvmorx2.c
(gxv_morx_subtable_type2_ligActionOffset_validate):
Conditionalize unvalidated variables; `last', `store'.
Checking for overrunning offset is added.
(gxv_morx_subtable_type2_entry_validate):
Conditionalize unvalidated variables; `setComponent',
`dontAdvance', `performAction'.
(gxv_morx_subtable_type2_ligatureTable_validate):
Check if the GID for ligature does not exceed the
max GID in `maxp' table.

* src/gxvalid/gxvmort5.c
(gxv_morx_subtable_type5_InsertList_validate):
Conditionalize unvalidated loading of `insert_glyphID'
array.  (gxv_morx_subtable_type5_entry_validate):
Conditionalize unvalidated variables; `setMark',
`dontAdvance', `currentIsKashidaLike',
`markedIsKashidaLike', `currentInsertBefore',
`markedInsertBefore'.