expr: fix ~ update onig/onig_sys dependency (fix windows compilation bugs)

* fixes compile bugs blocking compilation "onig_sys" (required for `expr`) on windows
  - MSVC/VS tools are no longer required to be prepped and available on the PATH (via
    `vsvarsall` or the "VCX command prompt")
  - GNU `gcc` compilation/targets are possible on windows
* restrict onig version to v4.3.2 (or later patches [only]; see discussion)

.# Discussion

onig v4.3.0/v4.3.1 inadvertently introduced a new minimum rust version (requiring
v1.31+; see https://github.com/rust-onig/rust-onig/issues/97). This was repaired with
v4.3.2 (requiring only v1.27.0+), and onig now specifies a rust minimum version that will
stay the same for patches, but may change between minor version increments.

src/expr/Cargo.toml

@@ -10,7 +10,7 @@ path = "expr.rs"
 
 [dependencies]
 libc = "0.2.42"
-onig = "3.1.1"
+onig = "~4.3.2"
 uucore = { path="../uucore" }
 
 [[bin]]