Improving build times with Google Mock - c++

Question

I'm looking for strategies to improve my build times with googletest and am wondering if what I'm seeing is typical, if there's a particular feature that can be avoided to improve build times, or if I'm just doing something wrong.
I have seen this post but its about 2 years old now.
I've been profiling with a moderately simple test fixture that has 24 tests and uses the following googlemock features. I apologize for not being able to provide a complete example here, but obviously for trivial examples, the build times are negligible. If you have experience on this topic and have a hunch, I can certainly fill in more details upon request. In total, the build is about 37 files including the googletest sources.
using ::testing::_;
using ::testing::AnyNumber;
using ::testing::DoAll;
using ::testing::Exactly;
using ::testing::InSequence;
using ::testing::Mock;
using ::testing::NiceMock;
using ::testing::Return;
using ::testing::SetArgReferee;
I've built my example with both clang 3.7.0 and mingw64-g++ 5.3.0 using cmake and ninja. See the times below. A full build is time required for all sources in project, including googletest. The compile+link is time required to build the single test fixture source and link. And link is time to create test executable. I tried the tuple flag, but as you can see, that didn't make much difference.
With the times as they are, they present some challenges for keeping the fix/build/test cycle snappy. It was interesting to me that configuration made such a huge difference and that Release was faster than Debug. I expected release to spend more time on optimizations.
GTEST_USE_OWN_TR1_TUPLE=1
Compiler | Config | Full | Compile+Link | Link
clang | Debug | 29.975s | 16.166s | 10.046s
clang | Release | 29.621s | 13.317s | 0.972s
mingw64 | Debug | 1m6.751s | 39.590s | 22.923s
mingw64 | Release | 44.287s | 15.075s | 1.031s
GTEST_USE_OWN_TR1_TUPLE=0
Compiler | Config | Full | Compile+Link | Link
clang | Debug | 28.565s | 15.815s | 9.545s
clang | Release | 28.354s | 12.955s | 1.075s
mingw64 | Debug | 1m7.954s | 37.611s | 24.304s
mingw64 | Release | 42.615s | 15.329s | 0.895s
Further dissection of the build time for the release clang build
#include <gmock/gmock.h> ~ 2s
Instantiating 11 mocks ~ 9s
24 test cases ~ 1s
EDIT:
I followed the advice in the cookbook - Making Compilation Faster, and that helped alot. I also did a comparison with release-1.6.0. I don't know what the consensus is regarding how fast is fast enough (0 seconds, -2 seconds, time travel?). Sub 10 seconds I start feeling is tolerable, 5 seconds is certainly preferred. Ideally, I would like to push this example sub 1 second, but perhaps that's not possible. Given that its a rather simple example, my hunch is that things won't hold under scale, but maybe that's not true.
googlemock 1.7+ ddb8012
GTEST_USE_OWN_TR1_TUPLE=0
Compiler | Config | Full | Compile+Link | Link
clang | Debug | 31.151s | 7.572s | 4.567s
clang | Release | 39.806s | 4.742s | 0.689s
googlemock 1.6
GTEST_USE_OWN_TR1_TUPLE=0
Compiler | Config | Full | Compile+Link | Link
clang | Debug | 26.551s | 5.104s | 3.218s
clang | Release | 28.932s | 3.777s | 0.676s