Do not use -Wl,--gc-sections for linux host libraries

This matches make

Change-Id: I2ee2e47065439afa02b946ede3a7718f1a8dc71b
diff --git a/cc/cc.go b/cc/cc.go
index 717e598..eb9c58f 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -1248,7 +1248,10 @@
 			sharedFlag = "-shared"
 		}
 		if ctx.Device() {
-			flags.LdFlags = append(flags.LdFlags, "-nostdlib")
+			flags.LdFlags = append(flags.LdFlags,
+				"-nostdlib",
+				"-Wl,--gc-sections",
+			)
 		}
 
 		if ctx.Darwin() {
@@ -1260,7 +1263,6 @@
 			)
 		} else {
 			flags.LdFlags = append(flags.LdFlags,
-				"-Wl,--gc-sections",
 				sharedFlag,
 				"-Wl,-soname,"+libName+flags.Toolchain.ShlibSuffix(),
 			)