Upgrade to DOS/32A 9.1.2.

Even if sources are updated too, it is basically a binary upgrade in bld/redist/dos32a as it was with 7.2 in OpenWatcom 1.0.
Idea will be to make ASM sources assemble with WASM instead of WASM, unfortunatelly Narech is not familiar with WASM, and I already forgot everything about internals on dos32a.