Set CMAKE_CXX_FLAGS only when not set

Author: accelerated

CMakeLists.txt

@@ -7,17 +7,20 @@ set(CPPKAFKA_VERSION_MINOR 2)
 set(CPPKAFKA_VERSION "${CPPKAFKA_VERSION_MAJOR}.${CPPKAFKA_VERSION_MINOR}")
 set(RDKAFKA_MIN_VERSION 0x00090400)
 
-if(MSVC)
-    # Don't always use Wall, since VC's /Wall is ridiculously verbose.
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W3")
-
-    # Disable VC secure checks, since these are not really issues
-    add_definitions("-D_CRT_SECURE_NO_WARNINGS=1")
-    add_definitions("-D_SCL_SECURE_NO_WARNINGS=1")
-    add_definitions("-DNOGDI=1")
-    add_definitions("-DNOMINMAX=1")
-else()
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall")
+if (NOT CMAKE_CXX_FLAGS)
+    # Set default compile flags for the project
+    if(MSVC)
+        # Don't always use Wall, since VC's /Wall is ridiculously verbose.
+        set(CMAKE_CXX_FLAGS "/W3")
+
+        # Disable VC secure checks, since these are not really issues
+        add_definitions("-D_CRT_SECURE_NO_WARNINGS=1")
+        add_definitions("-D_SCL_SECURE_NO_WARNINGS=1")
+        add_definitions("-DNOGDI=1")
+        add_definitions("-DNOMINMAX=1")
+    else()
+        set(CMAKE_CXX_FLAGS "-std=c++11 -Wall")
+    endif()
 endif()
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/cmake/")