diff --git a/tools/acp/Android.bp b/tools/acp/Android.bp
index faf2034e32..64f5a1013d 100644
--- a/tools/acp/Android.bp
+++ b/tools/acp/Android.bp
@@ -5,6 +5,7 @@
 cc_binary_host {
 
     srcs: ["acp.c"],
+    cflags: ["-Wall", "-Werror"],
 
     static_libs: ["libhost"],
     name: "acp",
diff --git a/tools/acp/acp.c b/tools/acp/acp.c
index eb1de1f96f..d4a9fbcf4d 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;
 
diff --git a/tools/atree/Android.bp b/tools/atree/Android.bp
index 3c3a8ef3ab..5fbe042ea2 100644
--- a/tools/atree/Android.bp
+++ b/tools/atree/Android.bp
@@ -9,5 +9,6 @@ cc_binary_host {
         "files.cpp",
         "fs.cpp",
     ],
+    cflags: ["-Wall", "-Werror"],
     static_libs: ["libhost"],
 }
diff --git a/tools/atree/files.cpp b/tools/atree/files.cpp
index d945f589c2..d5c8a977dd 100644
--- a/tools/atree/files.cpp
+++ b/tools/atree/files.cpp
@@ -425,8 +425,6 @@ list_dir(const string& path, const FileRecord& rec,
                 const vector<string>& excludes,
                 vector<FileRecord>* more)
 {
-    int err;
-
     string full = path_append(rec.sourceBase, rec.sourceName);
     full = path_append(full, path);
 
diff --git a/tools/fs_get_stats/Android.bp b/tools/fs_get_stats/Android.bp
index 6684319911..67742b8367 100644
--- a/tools/fs_get_stats/Android.bp
+++ b/tools/fs_get_stats/Android.bp
@@ -1,6 +1,7 @@
 cc_binary_host {
     name: "fs_get_stats",
     srcs: ["fs_get_stats.c"],
+    cflags: ["-Wall", "-Werror"],
     shared_libs: [
         "libcutils",
         "liblog",
diff --git a/tools/zipalign/Android.bp b/tools/zipalign/Android.bp
index cfc6aecdf0..2aa64504e5 100644
--- a/tools/zipalign/Android.bp
+++ b/tools/zipalign/Android.bp
@@ -13,6 +13,8 @@ cc_binary_host {
         "ZipFile.cpp",
     ],
 
+    cflags: ["-Wall", "-Werror"],
+
     static_libs: [
         "libandroidfw",
         "libutils",
diff --git a/tools/zipalign/ZipFile.cpp b/tools/zipalign/ZipFile.cpp
index 1b39902271..719c6b9bf5 100644
--- a/tools/zipalign/ZipFile.cpp
+++ b/tools/zipalign/ZipFile.cpp
@@ -785,8 +785,6 @@ status_t ZipFile::copyFpToFp(FILE* dstFp, FILE* srcFp, uint32_t* pCRC32)
 status_t ZipFile::copyDataToFp(FILE* dstFp,
     const void* data, size_t size, uint32_t* pCRC32)
 {
-    size_t count;
-
     *pCRC32 = crc32(0L, Z_NULL, 0);
     if (size > 0) {
         *pCRC32 = crc32(*pCRC32, (const unsigned char*)data, size);
diff --git a/tools/ziptime/Android.bp b/tools/ziptime/Android.bp
index 874d34685a..5ef45ed40a 100644
--- a/tools/ziptime/Android.bp
+++ b/tools/ziptime/Android.bp
@@ -27,6 +27,7 @@ cc_binary_host {
     ],
 
     name: "ziptime",
+    cflags: ["-Wall", "-Werror"],
     target: {
         windows: {
             enabled: true,
diff --git a/tools/ziptime/ZipEntry.cpp b/tools/ziptime/ZipEntry.cpp
index 51ce09f1fa..e7b52ed0a7 100644
--- a/tools/ziptime/ZipEntry.cpp
+++ b/tools/ziptime/ZipEntry.cpp
@@ -86,7 +86,6 @@ status_t ZipEntry::initAndRewriteFromCDE(FILE* fp)
  */
 status_t ZipEntry::LocalFileHeader::rewrite(FILE* fp)
 {
-    status_t result = 0;
     uint8_t buf[kLFHLen];
 
     if (fread(buf, 1, kLFHLen, fp) != kLFHLen)
@@ -124,7 +123,6 @@ status_t ZipEntry::LocalFileHeader::rewrite(FILE* fp)
  */
 status_t ZipEntry::CentralDirEntry::rewrite(FILE* fp)
 {
-    status_t result = 0;
     uint8_t buf[kCDELen];
     uint16_t fileNameLength, extraFieldLength, fileCommentLength;