append the modified CFLGAS do not replace them

diff --git a/.travis.yml b/.travis.yml
index e44cd25ded60a793edfbccf54624bf78c822eac7..12575ecaf65cd93e2e3ccf2c29aed4bcd13bcfb8 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,7 +16,7 @@ before_script:
 
 script:
   - ./configure --prefix=/opt/rrdtool-master
-  - make CFLAGS="-g -fprofile-arcs -ftest-coverage"
+  - make CFLAGS+="-g -O0 -fprofile-arcs -ftest-coverage"
   - make check
   - make check TESTS_STYLE=valgrind
   - sudo make install