diff --git a/CMakeLists.txt b/CMakeLists.txt
index bc4cb19bce0..0d7a6996980 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,6 +3,9 @@ cmake_minimum_required(VERSION 2.8.12)
 project(ceph CXX C ASM)
 set(VERSION 13.0.2)
 
+if(POLICY CMP0028)
+  cmake_policy(SET CMP0028 NEW)
+endif()
 if(POLICY CMP0046)
   # Tweak policies (this one disables "missing" dependency warning)
   cmake_policy(SET CMP0046 OLD)
diff --git a/cmake/modules/BuildBoost.cmake b/cmake/modules/BuildBoost.cmake
index 1bc28ad0f82..90fac55370d 100644
--- a/cmake/modules/BuildBoost.cmake
+++ b/cmake/modules/BuildBoost.cmake
@@ -140,7 +140,7 @@ function(do_build_boost version)
     # NOTE: If you change this version number make sure the package is available
     # at the three URLs below (may involve uploading to download.ceph.com)
     set(boost_version 1.66.0)
-    set(boost_md5 b2dfbd6c717be4a7bb2d88018eaccf75)
+    set(boost_256 5721818253e6a0989583192f96782c4a98eb6204965316df9f5ad75819225ca9)
     string(REPLACE "." "_" boost_version_underscore ${boost_version} )
     set(boost_url 
       https://dl.bintray.com/boostorg/release/${boost_version}/source/boost_${boost_version_underscore}.tar.bz2)
@@ -152,7 +152,7 @@ function(do_build_boost version)
     endif()
     set(source_dir
       URL ${boost_url}
-      URL_MD5 ${boost_md5})
+      URL_HASH SHA256=${boost_sha256})
     if(CMAKE_VERSION VERSION_GREATER 3.1)
       list(APPEND source_dir DOWNLOAD_NO_PROGRESS 1)
     endif()
diff --git a/cmake/modules/BuildRocksDB.cmake b/cmake/modules/BuildRocksDB.cmake
index 8e0ad577887..10dfc1b3c6b 100644
--- a/cmake/modules/BuildRocksDB.cmake
+++ b/cmake/modules/BuildRocksDB.cmake
@@ -1,7 +1,8 @@
 include(CheckCXXSourceRuns)
 
 function(do_build_rocksdb)
-    set(ROCKSDB_CMAKE_ARGS -DCMAKE_POSITION_INDEPENDENT_CODE=ON)
+  set(ROCKSDB_CMAKE_ARGS -DCMAKE_POSITION_INDEPENDENT_CODE=ON)
+  list(APPEND ROCKSDB_CMAKE_ARGS -DWITH_GFLAGS=OFF)
 
   if(ALLOCATOR STREQUAL "jemalloc")
     list(APPEND ROCKSDB_CMAKE_ARGS -DWITH_JEMALLOC=ON)
diff --git a/make-dist b/make-dist
index 29493b1ffc4..b0083882fce 100755
--- a/make-dist
+++ b/make-dist
@@ -23,7 +23,7 @@ fi
 download_boost() {
     boost_version=$1
     shift
-    boost_md5=$1
+    boost_sha256=$1
     shift
     boost_version_underscore=$(echo $boost_version | sed 's/\./_/g')
     boost_fname=boost_${boost_version_underscore}.tar.bz2
@@ -39,8 +39,8 @@ download_boost() {
         wget -c --no-verbose -O $boost_fname $url
         if [ $? != 0 -o ! -e $boost_fname ]; then
             echo "Download of $url failed"
-        elif [ $(md5sum $boost_fname | awk '{print $1}') != $boost_md5 ]; then
-            echo "Error: failed to download boost: MD5 mismatch."
+        elif [ $(sha256sum $boost_fname | awk '{print $1}') != $boost_sha256 ]; then
+            echo "Error: failed to download boost: SHA256 mismatch."
         else
             break
         fi
@@ -131,7 +131,7 @@ tar cvf $outfile.version.tar $outfile/src/.git_version $outfile/ceph.spec $outfi
 # NOTE: If you change this version number make sure the package is available
 # at the three URLs referenced below (may involve uploading to download.ceph.com)
 boost_version=1.66.0
-download_boost $boost_version b2dfbd6c717be4a7bb2d88018eaccf75 \
+download_boost $boost_version 5721818253e6a0989583192f96782c4a98eb6204965316df9f5ad75819225ca9 \
                https://dl.bintray.com/boostorg/release/$boost_version/source \
                https://downloads.sourceforge.net/project/boost/boost/$boost_version \
                https://download.ceph.com/qa
diff --git a/src/common/Preforker.h b/src/common/Preforker.h
index f6671a5d302..8925d944daa 100644
--- a/src/common/Preforker.h
+++ b/src/common/Preforker.h
@@ -108,7 +108,7 @@ public:
   int signal_exit(int r) {
     if (forked) {
       /* If we get an error here, it's too late to do anything reasonable about it. */
-      (void)safe_write(fd[1], &r, sizeof(r));
+      [[maybe_unused]] auto n = safe_write(fd[1], &r, sizeof(r));
     }
     return r;
   }
diff --git a/src/common/compat.cc b/src/common/compat.cc
index 18b75874ad0..66f6e7e8f6b 100644
--- a/src/common/compat.cc
+++ b/src/common/compat.cc
@@ -33,7 +33,7 @@ int manual_fallocate(int fd, off_t offset, off_t len) {
   // TODO: compressing filesystems would require random data
   memset(data, 0x42, sizeof(data));
   for (off_t off = 0; off < len; off += sizeof(data)) {
-    if (off + sizeof(data) > len)
+    if (off + static_cast<off_t>(sizeof(data)) > len)
       r = safe_write(fd, data, len - off);
     else
       r = safe_write(fd, data, sizeof(data));