updated the build matrix so builds don't fail...
diff --git a/.travis.yml b/.travis.yml
index 6cca5b1..99be2f9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -252,6 +252,22 @@
     # static code analysis
     - env: COMPILER=clang++-4.0 STATIC_CODE_ANALYSIS=true
 
+    # GCC 4.8
+    - env: COMPILER=g++-4.8 HAS_ASAN=true HAS_TSAN=true SANITIZER_CXX_FLAGS="-fuse-ld=gold" TSAN_CXX_FLAGS="-ltsan"
+      compiler: gcc
+    # GCC 4.9
+    - env: COMPILER=g++-4.9 HAS_ASAN=true HAS_UBSAN=true HAS_TSAN=true SANITIZER_CXX_FLAGS="-fuse-ld=gold" TSAN_CXX_FLAGS="-ltsan"
+      compiler: gcc
+    # GCC 5
+    - env: COMPILER=g++-5 HAS_ASAN=true HAS_UBSAN=true HAS_TSAN=true SANITIZER_CXX_FLAGS="-fuse-ld=gold" TSAN_CXX_FLAGS="-ltsan"
+      compiler: gcc
+    # GCC 6
+    - env: COMPILER=g++-6 HAS_ASAN=true HAS_UBSAN=true HAS_TSAN=true SANITIZER_CXX_FLAGS="-fuse-ld=gold" TSAN_CXX_FLAGS="-ltsan"
+      compiler: gcc
+    # GCC 7
+    - env: COMPILER=g++-7 HAS_ASAN=true HAS_UBSAN=true HAS_TSAN=true SANITIZER_CXX_FLAGS="-fuse-ld=gold" TSAN_CXX_FLAGS="-ltsan"
+      compiler: gcc
+
 install:
   - if [[ "${CODE_COVERAGE}" == "true" ]]; then gem install coveralls-lcov ; fi