diff --git a/.travis.yml b/.travis.yml
index 0db5b8e..101fd93 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -18,17 +18,20 @@ addons:
 dist: trusty
 sudo: false
 language: c
+
 before_install:
   - pip install --user cpp-coveralls
+
 script:
-  - CFLAGS="-fprofile-arcs -ftest-coverage -Werror" make all dunstify test-valgrind doc-doxygen
-  - coveralls
-compiler:
-  - gcc
-  - clang
-notifications:
-  irc:
-    channels:
-      - "chat.freenode.net#dunst"
-    on_success: change
-    on_failure: always
+  - CFLAGS="-Werror" make all dunstify test-valgrind doc-doxygen
+  - make clean
+  - CFLAGS="-Werror -fprofile-arcs -ftest-coverage -O0" make test
+
+matrix:
+  include:
+    - compiler: gcc
+      after_success:
+        - coveralls --exclude 'test'
+    - compiler: clang
+      after_success:
+        - coveralls --exclude 'test' --gcov llvm-cov --gcov-options gcov
diff --git a/config.mk b/config.mk
index 19cdb48..ae4844a 100644
--- a/config.mk
+++ b/config.mk
@@ -14,8 +14,8 @@ PKG_CONFIG ?= pkg-config
 
 # flags
 CPPFLAGS += -D_DEFAULT_SOURCE -DVERSION=\"${VERSION}\"
-CFLAGS   += -g --std=gnu99 -pedantic -Wall -Wno-overlength-strings -Os ${STATIC} ${CPPFLAGS}
-LDFLAGS  += -lm -L${X11LIB}
+CFLAGS   := -g --std=gnu99 -pedantic -Wall -Wno-overlength-strings -Os ${STATIC} ${CPPFLAGS} ${CFLAGS}
+LDFLAGS  := -lm ${LDFLAGS}
 
 CPPFLAGS_DEBUG := -DDEBUG_BUILD
 CFLAGS_DEBUG   := -O0