diff --git a/configure.ac b/configure.ac
index b1a7401..4b0760e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -95,16 +95,16 @@ if test "${GCC}" = "yes"; then
   TRY_CFLAGS([-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
-  TRY_CFLAGS([-g -O2 -g2 -Wall -Wmissing-declarations -Wdeclaration-after-statement -Wcast-align -Winline -Wsign-compare -Wnested-externs -Wpointer-arith -Wl,--as-needed -D_FORTIFY_SOURCE=2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security])
+  TRY_CFLAGS([-g -O2 -g2 -Wall -Wmissing-declarations -Wdeclaration-after-statement -Wcast-align -Wsign-compare -Wnested-externs -Wpointer-arith -Wmissing-prototypes -Wshadow -Wno-pointer-sign -D_FORTIFY_SOURCE=2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -Wl,--as-needed -Wl,--no-undefined])
 fi
 
 AC_CONFIG_FILES([Makefile src/Makefile doc/Makefile])
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 267a91c..cceb816 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -5,15 +5,26 @@ INCLUDE(CheckVariableExists)
 INCLUDE(CheckTypeSize)
 INCLUDE(CMakeDetermineCCompiler)
 
-IF(CMAKE_COMPILER_IS_GNUCC)
-	OPTION(BUILD_EXTRA_WARNINGS "extra warnings")
+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 -D_FORTIFY_SOURCE=2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security")
+	SET(WARN_LDFLAGS "-g -O2 -g2 -Wall -Wl,--as-needed -Wl,--no-undefined")
+	# -Werror
+ELSE(BUILD_EXTRA_WARNINGS)
+	SET(WARN_CFLAGS "")
+	SET(WARN_LDFLAGS "")
+ENDIF(BUILD_EXTRA_WARNINGS)
 
-	IF(BUILD_EXTRA_WARNINGS)
-		SET(WARN_FLAGS "-g -O2 -g2 -Wall -Wmissing-declarations -Wdeclaration-after-statement -Wcast-align -Winline -Wsign-compare -Wnested-externs -Wpointer-arith -Wl,--as-needed -D_FORTIFY_SOURCE=2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security")
-		# -Wno-pointer-sign -Werror -Wbad-function-cast -Wmissing-prototypes
-	ELSE(BUILD_EXTRA_WARNINGS)
-		SET(WARN_FLAGS "")
-	ENDIF(BUILD_EXTRA_WARNINGS)
+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)
 
 # awk '/#include <(.*)>/ { h = substr($2,2,length($2)-2); h2=toupper(h); gsub("\\.|\\/", "_", h2); printf "%s%s%s%s%s", "CHECK_INCLUDE_FILES(", h, " HAVE_", h2, ")\n" }' spawn-fcgi.c | sort
@@ -65,8 +76,7 @@ INCLUDE_DIRECTORIES(${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR})
 
 ADD_EXECUTABLE(spawn-fcgi spawn-fcgi.c)
 
-IF(CMAKE_COMPILER_IS_GNUCC)
-	SET_TARGET_PROPERTIES(spawn-fcgi PROPERTIES COMPILE_FLAGS "-std=gnu99 -Wall -g -Wshadow -W -pedantic -fPIC -D_GNU_SOURCE ${WARN_FLAGS}")
-ENDIF(CMAKE_COMPILER_IS_GNUCC)
+SET_TARGET_PROPERTIES(spawn-fcgi PROPERTIES COMPILE_FLAGS ${WARN_CFLAGS})
+TARGET_LINK_LIBRARIES(spawn-fcgi ${WARN_LDFLAGS})
 
 INSTALL(TARGETS spawn-fcgi DESTINATION bin)