Use -Werror in build/make

* Remove unused local variables.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: Iced5bb903902f49d7cd5cf5f572906a512c75e18
diff --git a/tools/acp/acp.c b/tools/acp/acp.c
index eb1de1f..d4a9fbc 100644
--- a/tools/acp/acp.c
+++ b/tools/acp/acp.c
@@ -41,10 +41,9 @@
 int process(int argc, char* const argv[], unsigned int options)
 {
     int retVal = 0;
-    int i, cc;
+    int i;
     char* stripDest = NULL;
     int stripDestLen;
-    struct stat destStat;
     bool destMustBeDir = false;
     struct stat sb;