unix: convert Iovec.Base to *byte in mkpost.go on solaris

Instead of defining a dedicated type goIovec with the correct *byte type
for its Base field like CL 412496 did, modify the Base field of the
original type Iovec (generated from struct iovec) in mkpost.go. This is
akin to how we already change []int8 to []byte for several other types.

Fixes golang/go#55997

Change-Id: If30799bb2bfe6d17678370b45348ff0b7c5de2e9
Reviewed-on: https://go-review.googlesource.com/c/sys/+/484635
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>

unix/mkpost.go

@@ -101,6 +101,17 @@ func main() {
 		})
 	}
 
+	if goos == "solaris" {
+		// Convert *int8 to *byte in Iovec.Base like on every other platform.
+		convertIovecBase := regexp.MustCompile(`Base\s+\*int8`)
+		iovecType := regexp.MustCompile(`type Iovec struct {[^}]*}`)
+		iovecStructs := iovecType.FindAll(b, -1)
+		for _, s := range iovecStructs {
+			newNames := convertIovecBase.ReplaceAll(s, []byte("Base *byte"))
+			b = bytes.Replace(b, s, newNames, 1)
+		}
+	}
+
 	// Intentionally export __val fields in Fsid and Sigset_t
 	valRegex := regexp.MustCompile(`type (Fsid|Sigset_t) struct {(\s+)X__(bits|val)(\s+\S+\s+)}`)
 	b = valRegex.ReplaceAll(b, []byte("type $1 struct {${2}Val$4}"))

unix/types_solaris.go

@@ -76,12 +76,6 @@ struct sockaddr_any {
 	char pad[sizeof(union sockaddr_all) - sizeof(struct sockaddr)];
 };
 
-// go_iovec is used to get *byte as the base address for Iovec.
-struct goIovec {
-	void*  iov_base;
-	size_t iov_len;
-};
-
 // Solaris and the major illumos distributions ship a 3rd party tun/tap driver
 // from https://github.com/kaizawa/tuntap
 // It supports a pair of IOCTLs defined at
@@ -164,7 +158,7 @@ type _Socklen C.socklen_t
 
 type Linger C.struct_linger
 
-type Iovec C.struct_goIovec
+type Iovec C.struct_iovec
 
 type IPMreq C.struct_ip_mreq