diff --git a/android-config b/android-config
index 562660a7..7c8ada3c 100755
--- a/android-config
+++ b/android-config
@@ -36,6 +36,11 @@ PATH=$TOOLCHAIN/bin:$PATH
     --host=arm-linux-androideabi \
     --build=`dpkg-architecture -qDEB_BUILD_GNU_TYPE` \
     --with-xml-prefix="$PREFIX" \
+    --disable-python-bindings \
+    --disable-examples \
+    --enable-werror \
+    CC=clang \
+    CXX=clang++ \
     CPPFLAGS="-I$PREFIX/include" \
     PKG_CONFIG_LIBDIR="$PREFIX/lib/pkgconfig" \
     LDFLAGS="-L$PREFIX/lib"
diff --git a/lib/nghttp2_session.c b/lib/nghttp2_session.c
index 291e4ba5..e1e65d68 100644
--- a/lib/nghttp2_session.c
+++ b/lib/nghttp2_session.c
@@ -1784,6 +1784,7 @@ static int session_prep_frame(nghttp2_session *session,
   } else {
     /* Unreachable */
     assert(0);
+    return 0;
   }
 }
 
@@ -2221,6 +2222,7 @@ static int session_after_frame_sent(nghttp2_session *session)
   }
   /* Unreachable */
   assert(0);
+  return 0;
 }
 
 ssize_t nghttp2_session_mem_send(nghttp2_session *session,
diff --git a/src/shrpx_http2_session.cc b/src/shrpx_http2_session.cc
index aff15436..41bb1e00 100644
--- a/src/shrpx_http2_session.cc
+++ b/src/shrpx_http2_session.cc
@@ -520,6 +520,7 @@ int Http2Session::initiate_connection()
 
   // Unreachable
   DIE();
+  return 0;
 }
 
 void Http2Session::unwrap_free_bev()
diff --git a/src/timegm.c b/src/timegm.c
index ac848d23..e5bdbab8 100644
--- a/src/timegm.c
+++ b/src/timegm.c
@@ -69,7 +69,7 @@ time_t timegm(struct tm *tm)
       return -1;
     }
   }
-  return t;
+  return (time_t)t;
 }
 
 #endif /* !HAVE_TIMEGM */