diff --git a/.travis.yml b/.travis.yml
index 417d2c51..fa25abea 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,11 @@ install:
 # /usr/bin/gcc is 4.6 always, but gcc-X.Y is available.
 - if [ "$CXX" = "g++" ]; then export CXX="g++-4.9" CC="gcc-4.9"; fi
 # /usr/bin/clang is 3.4, lets override with modern one.
-- if [ "$CXX" = "clang++" ] && [ "$TRAVIS_OS_NAME" = "linux" ]; then export CXX="clang++-3.7" CC="clang-3.7"; fi
+- if [ "$CXX" = "clang++" ] && [ "$TRAVIS_OS_NAME" = "linux" ]; then export CXX="clang++-3.7" CC="clang-3.7"; ln -sf /usr/bin/ccache /$HOME/bin/$CXX; ln -sf /usr/bin/ccache /$HOME/bin/$CC; fi
+# ccache on OS X needs installation first
+- if [ "$TRAVIS_OS_NAME" = "osx" ]; then brew install ccache; export PATH="/usr/local/opt/ccache/libexec:$PATH"; fi
+# reset ccache statistics
+- ccache --zero-stats
 - echo ${PATH}
 - echo ${CXX}
 - ${CXX} --version
@@ -22,14 +26,16 @@ addons:
     - ubuntu-toolchain-r-test
     - llvm-toolchain-precise-3.7
     packages:
-    - gcc-4.9
     - g++-4.9
     - clang-3.7
-    - valgrind
 os:
   - linux
   - osx
 language: cpp
+cache: ccache
+before_cache:
+  # print statistics before uploading new cache
+  - ccache --show-stats
 compiler:
   - gcc
   - clang
@@ -37,7 +43,7 @@ script: ./travis.sh
 env:
   matrix:
     - SHARED_LIB=OFF STATIC_LIB=ON CMAKE_PKG=OFF BUILD_TYPE=Debug VERBOSE=1
-    - SHARED_LIB=OFF STATIC_LIB=ON CMAKE_PKG=OFF BUILD_TYPE=Debug VERBOSE=1 CXX_FLAGS=-std=c++11
+    - SHARED_LIB=OFF STATIC_LIB=ON CMAKE_PKG=OFF BUILD_TYPE=Release VERBOSE=1 CXX_FLAGS=-std=c++11
 notifications:
   email: false
 sudo: false
diff --git a/googlemock/CMakeLists.txt b/googlemock/CMakeLists.txt
index bd759dfd..724fdd5f 100644
--- a/googlemock/CMakeLists.txt
+++ b/googlemock/CMakeLists.txt
@@ -164,7 +164,7 @@ if (gmock_build_tests)
   cxx_test(gmock_link_test gmock_main test/gmock_link2_test.cc)
   cxx_test(gmock_test gmock_main)
 
-  if (CMAKE_USE_PTHREADS_INIT)
+  if (DEFINED GTEST_HAS_PTHREAD)
     cxx_test(gmock_stress_test gmock)
   endif()
 
diff --git a/googletest/cmake/internal_utils.cmake b/googletest/cmake/internal_utils.cmake
index ec5d08c0..9915c11f 100644
--- a/googletest/cmake/internal_utils.cmake
+++ b/googletest/cmake/internal_utils.cmake
@@ -48,10 +48,14 @@ endmacro()
 macro(config_compiler_and_linker)
   # Note: pthreads on MinGW is not supported, even if available
   # instead, we use windows threading primitives
+  unset(GTEST_HAS_PTHREAD)
   if (NOT gtest_disable_pthreads AND NOT MINGW)
     # Defines CMAKE_USE_PTHREADS_INIT and CMAKE_THREAD_LIBS_INIT.
     set(THREADS_PREFER_PTHREAD_FLAG ON)
     find_package(Threads)
+    if (CMAKE_USE_PTHREADS_INIT)
+      set(GTEST_HAS_PTHREAD ON)
+    endif()
   endif()
 
   fix_default_compiler_settings_()
@@ -94,7 +98,7 @@ macro(config_compiler_and_linker)
     set(cxx_no_exception_flags "-D_HAS_EXCEPTIONS=0")
     set(cxx_no_rtti_flags "-GR-")
   elseif (CMAKE_COMPILER_IS_GNUCXX)
-    set(cxx_base_flags "-Wall -Wshadow")
+    set(cxx_base_flags "-Wall -Wshadow -Werror")
     set(cxx_exception_flags "-fexceptions")
     set(cxx_no_exception_flags "-fno-exceptions")
     # Until version 4.3.2, GCC doesn't define a macro to indicate
@@ -126,7 +130,8 @@ macro(config_compiler_and_linker)
     set(cxx_no_rtti_flags "")
   endif()
 
-  if (CMAKE_USE_PTHREADS_INIT)  # The pthreads library is available and allowed.
+  # The pthreads library is available and allowed?
+  if (DEFINED GTEST_HAS_PTHREAD)
     set(GTEST_HAS_PTHREAD_MACRO "-DGTEST_HAS_PTHREAD=1")
   else()
     set(GTEST_HAS_PTHREAD_MACRO "-DGTEST_HAS_PTHREAD=0")
@@ -159,7 +164,7 @@ function(cxx_library_with_type name type cxx_flags)
       PROPERTIES
       COMPILE_DEFINITIONS "GTEST_CREATE_SHARED_LIBRARY=1")
   endif()
-  if (CMAKE_USE_PTHREADS_INIT)
+  if (DEFINED GTEST_HAS_PTHREAD)
     target_link_libraries(${name} ${CMAKE_THREAD_LIBS_INIT})
   endif()
 endfunction()
diff --git a/googletest/test/gtest-param-test_test.cc b/googletest/test/gtest-param-test_test.cc
index 857f6c5e..d1b0644f 100644
--- a/googletest/test/gtest-param-test_test.cc
+++ b/googletest/test/gtest-param-test_test.cc
@@ -857,8 +857,8 @@ TEST_P(CustomLambdaNamingTest, CustomTestNames) {}
 INSTANTIATE_TEST_CASE_P(CustomParamNameLambda,
                         CustomLambdaNamingTest,
                         Values(std::string("LambdaName")),
-                        [](const ::testing::TestParamInfo<std::string>& info) {
-                          return info.param;
+                        [](const ::testing::TestParamInfo<std::string>& tpinfo) {
+                          return tpinfo.param;
                         });
 
 #endif  // GTEST_LANG_CXX11
diff --git a/googletest/test/gtest_unittest.cc b/googletest/test/gtest_unittest.cc
index f84def90..745c9506 100644
--- a/googletest/test/gtest_unittest.cc
+++ b/googletest/test/gtest_unittest.cc
@@ -2096,7 +2096,7 @@ class UnitTestRecordPropertyTestEnvironment : public Environment {
 };
 
 // This will test property recording outside of any test or test case.
-static Environment* record_property_env =
+Environment* record_property_env GTEST_ATTRIBUTE_UNUSED_ =
     AddGlobalTestEnvironment(new UnitTestRecordPropertyTestEnvironment);
 
 // This group of tests is for predicate assertions (ASSERT_PRED*, etc)
diff --git a/travis.sh b/travis.sh
index bd226a8d..24a557e9 100755
--- a/travis.sh
+++ b/travis.sh
@@ -1,5 +1,25 @@
 #!/usr/bin/env sh
 set -evx
+
+# if possible, ask for the precise number of processors,
+# otherwise take 2 processors as reasonable default; see
+# https://docs.travis-ci.com/user/speeding-up-the-build/#Makefile-optimization
+if [ -x /usr/bin/getconf ]; then
+    NPROCESSORS=$(/usr/bin/getconf _NPROCESSORS_ONLN)
+else
+    NPROCESSORS=2
+fi
+# as of 2017-09-04 Travis CI reports 32 processors, but GCC build
+# crashes if parallelized too much (maybe memory consumption problem),
+# so limit to 4 processors for the time being.
+if [ $NPROCESSORS -gt 4 ] ; then
+	echo "$0:Note: Limiting processors to use by make from $NPROCESSORS to 4."
+	NPROCESSORS=4
+fi
+# Tell make to use the processors. No preceding '-' required.
+MAKEFLAGS="j${NPROCESSORS}"
+export MAKEFLAGS
+
 env | sort
 
 mkdir build || true