diff --git a/.travis.yml b/.travis.yml
index eb3ad741..438bf4d0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -112,5 +112,5 @@ script:
   # NNUE testing / TODO should work with debug=yes as well
   #
   - export CXXFLAGS="-O1 -fno-inline"
-  - if [ -x "$(command -v valgrind )" ]; then make clean && make -j2 ARCH=x86-64-modern debug=no optimize=no learn > /dev/null && ../tests/instrumented_learn.sh --valgrind; fi
-  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then make clean && make -j2 ARCH=x86-64-modern sanitize=undefined optimize=no debug=no learn > /dev/null && ../tests/instrumented_learn.sh --sanitizer-undefined; fi
+  - if [ -x "$(command -v valgrind )" ]; then make clean && LDFLAGS="-lstdc++fs"  make -j2 ARCH=x86-64-modern debug=no optimize=no learn > /dev/null && ../tests/instrumented_learn.sh --valgrind; fi
+  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then make clean && LDFLAGS="-lstdc++fs"  make -j2 ARCH=x86-64-modern sanitize=undefined optimize=no debug=no learn > /dev/null && ../tests/instrumented_learn.sh --sanitizer-undefined; fi