diff --git a/source/shared_lib/CMakeLists.txt b/source/shared_lib/CMakeLists.txt
index bd1806138..b478ca3a0 100644
--- a/source/shared_lib/CMakeLists.txt
+++ b/source/shared_lib/CMakeLists.txt
@@ -7,7 +7,7 @@ add_definitions("-DDATADIR=${INSTALL_DIR_DATA}")
 
 # On Travis, the build fails on osx and Ubuntu trusty using
 # clang 5.0 unless the -std=c++11 if used
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall")
 
 if(WANT_USE_STREFLOP)
 	# IMPORTANT: should come BEFORE finding packages