[build] improve (warning) compile flags

CMakeLists.txt

@@ -27,6 +27,21 @@ IF("${CMAKE_BUILD_TYPE}" STREQUAL "")
 	SET(CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "Choose the type of build, options are: None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used) Debug Release RelWithDebInfo MinSizeRel." FORCE)
 ENDIF("${CMAKE_BUILD_TYPE}" STREQUAL "")
 
+OPTION(BUILD_EXTRA_WARNINGS "extra warnings")
+
+# default to ON
+set(CMAKE_POSITION_INDEPENDENT_CODE ON CACHE BOOL "Default value for ``POSITION_INDEPENDENT_CODE`` of targets.")
+
+IF(BUILD_EXTRA_WARNINGS)
+	SET(WARN_CFLAGS "-g -O2 -g2 -Wall -Wmissing-declarations -Wdeclaration-after-statement -Wcast-align -Wsign-compare -Wnested-externs -Wpointer-arith -Wmissing-prototypes -Wshadow -Wno-pointer-sign -Wformat-security")
+	SET(WARN_LDFLAGS "-g -O2 -g2 -Wall -Wl,--as-needed -Wl,--no-undefined")
+	# -Wl,--as-needed
+	# -Werror -Wbad-function-cast -Wmissing-prototypes
+ELSE(BUILD_EXTRA_WARNINGS)
+	SET(WARN_CFLAGS "")
+	SET(WARN_LDFLAGS "")
+ENDIF(BUILD_EXTRA_WARNINGS)
+
 
 # libev
 CHECK_INCLUDE_FILES(ev.h HAVE_EV_H)
@@ -61,7 +76,16 @@ INCLUDE_DIRECTORIES(${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR})
 
 add_executable(multiwatch ${MAIN_SOURCE})
 
-ADD_TARGET_PROPERTIES(multiwatch COMPILE_FLAGS "-std=gnu99 -Wall -g -Wshadow -W -pedantic -fPIC -D_GNU_SOURCE")
+IF(CMAKE_COMPILER_IS_GNUCC)
+	SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99 -Wall -g -Wshadow -W -pedantic")
+	SET(CMAKE_C_FLAGS_RELEASE        "${CMAKE_C_FLAGS_RELEASE}     -O2")
+	SET(CMAKE_C_FLAGS_DEBUG          "${CMAKE_C_FLAGS_DEBUG}       -O0")
+	SET(CMAKE_C_FLAGS_RELWITHDEBINFO "${CMAKE_C_FLAGS_WITHDEBINFO} -O2")
+	ADD_DEFINITIONS(-D_GNU_SOURCE)
+ENDIF(CMAKE_COMPILER_IS_GNUCC)
+
+ADD_TARGET_PROPERTIES(multiwatch COMPILE_FLAGS "${WARN_CFLAGS}")
+TARGET_LINK_LIBRARIES(multiwatch ${WARN_LDFLAGS})
 
 # libev
 TARGET_LINK_LIBRARIES(multiwatch "${EV_LIBRARIES}")

configure.ac

@@ -23,9 +23,9 @@ PKG_CHECK_MODULES(GLIB, glib-2.0 >= 2.16.0, [
 # lib ev
 AC_CHECK_HEADERS([ev.h], [], [AC_MSG_ERROR("ev.h not found")])
 AC_CHECK_LIB([ev], [ev_time], [
-	LIBS="-lev ${LIBS}"
-	AC_DEFINE([HAVE_LIBEV], [1], [ev_time in -lev])
-	], [AC_MSG_ERROR("libev not found")])
+  LIBS="-lev ${LIBS}"
+  AC_DEFINE([HAVE_LIBEV], [1], [ev_time in -lev])
+], [AC_MSG_ERROR("libev not found")])
 
 # Checks for header files.
 AC_CHECK_HEADERS([stdlib.h unistd.h], [])
@@ -41,16 +41,16 @@ if test "${GCC}" = "yes"; then
     CFLAGS="${CFLAGS} -Wall -W -Wshadow -pedantic -std=gnu99"
 fi
 
-AC_ARG_ENABLE(extra-warnings,
- AC_HELP_STRING([--enable-extra-warnings],[enable extra warnings (gcc specific)]),
+AC_ARG_ENABLE([extra-warnings],
+ [AS_HELP_STRING([--enable-extra-warnings],[enable extra warnings (gcc specific)])],
  [case "${enableval}" in
    yes) extrawarnings=true ;;
     no) extrawarnings=false ;;
-     *) AC_MSG_ERROR(bad value ${enableval} for --enable-extra-warnings) ;;
+     *) AC_MSG_ERROR([bad value ${enableval} for --enable-extra-warnings]) ;;
   esac],[extrawarnings=false])
 
 if test x$extrawarnings = xtrue; then
-    CFLAGS="${CFLAGS} -g -O2 -g2 -Wall -Wmissing-declarations -Wdeclaration-after-statement -Wno-pointer-sign -Wcast-align -Winline -Wsign-compare -Wnested-externs -Wpointer-arith -Wl,--as-needed -Wformat-security"
+    CFLAGS="${CFLAGS} -g -O2 -g2 -Wall -Wmissing-declarations -Wdeclaration-after-statement -Wcast-align -Wsign-compare -Wnested-externs -Wpointer-arith -Wmissing-prototypes -Wshadow -Wno-pointer-sign -Wformat-security -Wl,--as-needed -Wl,--no-undefined"
 fi
 
 AC_CONFIG_FILES([Makefile])