ld: mark PE executables as terminal services aware

This has been the default in MSVC for a very long time, and it's hard to
imagine modern programs actually wanting the old legacy behavior. For
example, no modern programs try to install their junk into C:\windows
and therefore need to have an emulated writable windows directory.
That's not really even allowed by ACLs on modern systems.

Change-Id: Iadaca6815e39ea5c6b05c1cac5a95cfc35e5b48a
Reviewed-on: https://go-review.googlesource.com/c/go/+/191840
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

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

@@ -1172,6 +1172,9 @@ func (ctxt *Link) hostlink() {
 		} else {
 			argv = append(argv, "-mconsole")
 		}
+		// Mark as having awareness of terminal services, to avoid
+		// ancient compatibility hacks.
+		argv = append(argv, "-Wl,--tsaware")
 	case objabi.Haix:
 		argv = append(argv, "-pthread")
 		// prevent ld to reorder .text functions to keep the same

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

@@ -96,6 +96,7 @@ const (
 	IMAGE_SUBSYSTEM_WINDOWS_CUI                    = 3
 	IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE          = 0x0040
 	IMAGE_DLLCHARACTERISTICS_NX_COMPAT             = 0x0100
+	IMAGE_DLLCHARACTERISTICS_TERMINAL_SERVER_AWARE = 0x8000
 )
 
 // TODO(crawshaw): add these constants to debug/pe.
@@ -859,6 +860,10 @@ func (f *peFile) writeOptionalHeader(ctxt *Link) {
 		oh.DllCharacteristics = IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE | IMAGE_DLLCHARACTERISTICS_NX_COMPAT
 	}
 
+	// Mark as having awareness of terminal services, to avoid ancient compatibility hacks.
+	oh64.DllCharacteristics |= IMAGE_DLLCHARACTERISTICS_TERMINAL_SERVER_AWARE
+	oh.DllCharacteristics |= IMAGE_DLLCHARACTERISTICS_TERMINAL_SERVER_AWARE
+
 	// Disable stack growth as we don't want Windows to
 	// fiddle with the thread stack limits, which we set
 	// ourselves to circumvent the stack checks in the