cmd/link: fix flags order in linkerFlagSupported

Flags from CGo directives should be placed before extldflags so that
extldflags get more preference. This is also the order followed by the
final link command.

Fixes #69350

Change-Id: I2cfb22ae4ea7a160cc614440e88ef2eb82ea7399
Reviewed-on: https://go-review.googlesource.com/c/go/+/614275
Reviewed-by: Cherry Mui <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
Commit-Queue: Ian Lance Taylor <[email protected]>

Author: siddharthab

src/cmd/link/internal/ld/lib.go

@@ -2133,7 +2133,7 @@ func linkerFlagSupported(arch *sys.Arch, linker, altLinker, flag string) bool {
 
 	flags := hostlinkArchArgs(arch)
 
-	moreFlags := trimLinkerArgv(append(flagExtldflags, ldflag...))
+	moreFlags := trimLinkerArgv(append(ldflag, flagExtldflags...))
 	flags = append(flags, moreFlags...)
 
 	if altLinker != "" {