Fix InstallBypassMake symlink dependencies

Host symlinks cannot use order-only dependencies because they may be
used as part of the dependency chain on a tool, and an order-only
dependency would cause the target of the symlink not to be updated.
Use regular dependencies instead.

Bug: 204136549
Fixes: 205674000
Test: TestInstallBypassMake
Change-Id: Ib3f4ee143e94d1995ec6c60d314e7c91e57cc775
diff --git a/android/makevars.go b/android/makevars.go
index 7d8864a..8825d1a 100644
--- a/android/makevars.go
+++ b/android/makevars.go
@@ -473,15 +473,19 @@
 
 	for _, symlink := range symlinks {
 		fmt.Fprintf(buf, "%s:", symlink.to.String())
+		if symlink.from != nil {
+			// The symlink doesn't need updating when the target is modified, but we sometimes
+			// have a dependency on a symlink to a binary instead of to the binary directly, and
+			// the mtime of the symlink must be updated when the binary is modified, so use a
+			// normal dependency here instead of an order-only dependency.
+			fmt.Fprintf(buf, " %s", symlink.from.String())
+		}
 		for _, dep := range symlink.implicitDeps {
 			fmt.Fprintf(buf, " %s", dep.String())
 		}
-		if symlink.from != nil || len(symlink.orderOnlyDeps) > 0 {
+		if len(symlink.orderOnlyDeps) > 0 {
 			fmt.Fprintf(buf, " |")
 		}
-		if symlink.from != nil {
-			fmt.Fprintf(buf, " %s", symlink.from.String())
-		}
 		for _, dep := range symlink.orderOnlyDeps {
 			fmt.Fprintf(buf, " %s", dep.String())
 		}