diff --git a/CI/build_win.ps1 b/CI/build_win.ps1
index 9f244ddbe..56f745279 100644
--- a/CI/build_win.ps1
+++ b/CI/build_win.ps1
@@ -7,5 +7,5 @@ $src_dir=$pwd
 mkdir build
 cd build
 
-cmake -G "$COMPILER" -A "$ARCH" -DPYTHON_BINDINGS=ON -DLIBXML2_LIBRARIES="$src_dir\deps\lib\libxml2.dll.a" ..
+cmake -G "$COMPILER" -A "$ARCH" -DENABLE_IPV6=OFF -DWITH_USB_BACKEND=OFF -DWITH_SERIAL_BACKEND=OFF -DPYTHON_BINDINGS=ON -DLIBXML2_LIBRARIES="$src_dir\deps\lib\libxml2.dll.a" ..
 cmake --build . --config Release
diff --git a/CI/travis/before_install_darwin b/CI/travis/before_install_darwin
index 166077203..bf6cfc25d 100755
--- a/CI/travis/before_install_darwin
+++ b/CI/travis/before_install_darwin
@@ -2,4 +2,4 @@
 
 . CI/travis/lib.sh
 
-brew_install_if_not_exists cmake doxygen libusb libxml2 ncurses cdk
+brew_install_if_not_exists cmake doxygen libusb libxml2 ncurses cdk zstd
diff --git a/CI/travis/before_install_linux b/CI/travis/before_install_linux
index 3cdc3844f..db248fd65 100755
--- a/CI/travis/before_install_linux
+++ b/CI/travis/before_install_linux
@@ -27,7 +27,7 @@ handle_centos() {
 	# FIXME: see about adding `libserialport-dev` from EPEL ; maybe libusb-1.0.0-devel...
 	yum -y groupinstall 'Development Tools'
 	yum -y install cmake libxml2-devel libusb1-devel libaio-devel \
-		bzip2 gzip rpm rpm-build
+		bzip2 gzip rpm rpm-build libzstd-devel
 
 	if [ "$(get_version | head -c 1)" = "7" ] ; then
 		# install Cmake3, and make it the default
@@ -66,7 +66,7 @@ handle_generic_docker() {
 handle_default() {
 	sudo apt-get -qq update
 	sudo DEBIAN_FRONTEND=noninteractive apt-get install -y cmake graphviz \
-		libaio-dev libavahi-client-dev libserialport-dev \
+		libaio-dev libavahi-client-dev libserialport-dev libzstd-dev \
 		libavahi-common-dev libusb-1.0-0-dev libxml2-dev rpm tar \
 		bzip2 gzip flex bison git libncurses5-dev libcdk5-dev \
 		doxygen man2html python3 python3-pip python3-setuptools
diff --git a/CI/travis/make_darwin b/CI/travis/make_darwin
index be729ebaa..52902598c 100755
--- a/CI/travis/make_darwin
+++ b/CI/travis/make_darwin
@@ -1,5 +1,7 @@
 #!/bin/sh -e
 
+LIBIIO_BUILD_CONF="-DWITH_SERIAL_BACKEND=OFF -DWITH_ZSTD=ON"
+
 if [ "x${COVERITY_SCAN_PROJECT_NAME}" != "x" ] ; then exit 0; fi
 
 
@@ -18,13 +20,13 @@ build_osx() {
 mkdir -p build
 
 cd build
-build_osx "-DOSX_PACKAGE=ON -DPYTHON_BINDINGS=ON -DWITH_EXAMPLES=ON"
+build_osx "-DOSX_PACKAGE=ON -DPYTHON_BINDINGS=ON -DWITH_EXAMPLES=ON ${LIBIIO_BUILD_CONF}"
 
 cd ..
 
 mkdir -p build_tar
 cd build_tar
-build_osx "-DOSX_PACKAGE=OFF -DENABLE_PACKAGING=ON -DPYTHON_BINDINGS=ON"
+build_osx "-DOSX_PACKAGE=OFF -DENABLE_PACKAGING=ON -DPYTHON_BINDINGS=ON ${LIBIIO_BUILD_CONF}"
 echo "### make package"
 make package
 echo "### files are"
diff --git a/CI/travis/make_linux b/CI/travis/make_linux
index d215d4d6f..cf732d5d1 100755
--- a/CI/travis/make_linux
+++ b/CI/travis/make_linux
@@ -44,6 +44,13 @@ handle_default() {
 
 	FLAGS="-DENABLE_PACKAGING=ON -DDEB_DETECT_DEPENDENCIES=ON -DWITH_EXAMPLES=ON ${PYTHON_HELP} ${DOC_HELP} ${MAN_HELP}"
 
+	# Ubuntu Xenial's libserialport and libzstd are too old
+	if [ "${OS_VERSION}" = xenial ] ; then
+		FLAGS="${FLAGS} -DWITH_SERIAL_BACKEND=OFF"
+	else
+		FLAGS="${FLAGS} -DWITH_ZSTD=ON"
+	fi
+
 	echo "### cmake ${FLAGS}"
 	cmake ${FLAGS} ..
 
@@ -103,7 +110,13 @@ handle_centos() {
 	echo "handle centos"
 	mkdir -p build
 	cd build
-	cmake -DENABLE_PACKAGING=ON -DPYTHON_BINDINGS=ON ..
+
+	FLAGS="-DENABLE_PACKAGING=ON -DPYTHON_BINDINGS=ON -DWITH_SERIAL_BACKEND=OFF -DWITH_ZSTD=ON"
+
+	# CentOS 7's kernel headers are too old for USB support in IIOD
+	[ "${OS_VERSION}" = centos7 ] && FLAGS="${FLAGS} -DWITH_IIOD_USBD=OFF"
+
+	cmake ${FLAGS} ..
 	make
 	make package
 	cd ..
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6eac89549..d3ed0a2cd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -37,7 +37,7 @@ if (NOT CMAKE_BUILD_TYPE)
 	set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS None Debug Release RelWithDebInfo MinSizeRel)
 endif()
 
-set(BUILD_SHARED_LIBS ON CACHE BOOL "Build shared libraries")
+option(BUILD_SHARED_LIBS "Build shared libraries" ON)
 
 if (NOT BUILD_SHARED_LIBS)
 	add_definitions(-DLIBIIO_STATIC=1)
@@ -120,9 +120,6 @@ endif()
 if(APPLE)
 	#full Single Unix Standard v3 (SUSv3) conformance (the Unix API)
 	add_definitions(-D_DARWIN_C_SOURCE)
-elseif (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
-	set(CMAKE_REQUIRED_DEFINITIONS "-D_GNU_SOURCE=1")
-	add_definitions(-D_GNU_SOURCE=1)
 elseif (${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD|DragonFly|OpenBSD|NetBSD")
 	set(CMAKE_REQUIRED_DEFINITIONS "-D__BSD_VISIBLE")
 	add_definitions(-D__BSD_VISIBLE=1)
@@ -135,29 +132,25 @@ check_symbol_exists(strndup "string.h" HAS_STRNDUP)
 check_symbol_exists(strerror_r "string.h" HAS_STRERROR_R)
 check_symbol_exists(newlocale "locale.h" HAS_NEWLOCALE)
 
-if (NOT WIN32)
-	find_library(PTHREAD_LIBRARIES pthread)
-	set(CMAKE_REQUIRED_LIBRARIES ${PTHREAD_LIBRARIES})
-	check_symbol_exists(pthread_setname_np "pthread.h" HAS_PTHREAD_SETNAME_NP)
-	set(CMAKE_REQUIRED_LIBRARIES)
-endif()
-
 option(ENABLE_IPV6 "Define if you want to enable IPv6 support" ON)
 if (ENABLE_IPV6)
 	check_symbol_exists(in6addr_any "netinet/in.h" HAVE_IPV6)
 	if (NOT HAVE_IPV6)
-		message(WARNING "IPv6 is not available in your system.")
+		message(SEND_ERROR "IPv6 is not available in your system.")
 	endif()
 endif()
 
-#Handle FreeBSD libusb and Linux libusb-1.0 libraries
-find_library(LIBUSB_LIBRARIES NAMES usb-1.0 usb)
-find_path(LIBUSB_INCLUDE_DIR libusb.h PATH_SUFFIXES libusb-1.0)
-if (LIBUSB_LIBRARIES AND LIBUSB_INCLUDE_DIR)
-	message(STATUS "Looking for libusb-1.0 : Found")
-	option(WITH_USB_BACKEND "Enable the libusb backend" ON)
+option(WITH_USB_BACKEND "Enable the libusb backend" ON)
+if (WITH_USB_BACKEND)
+	#Handle FreeBSD libusb and Linux libusb-1.0 libraries
+	find_library(LIBUSB_LIBRARIES NAMES usb-1.0 usb)
+	find_path(LIBUSB_INCLUDE_DIR libusb.h PATH_SUFFIXES libusb-1.0)
+	if (NOT LIBUSB_LIBRARIES OR NOT LIBUSB_INCLUDE_DIR)
+		message(SEND_ERROR "Unable to find libusb-1.0 dependency.\n"
+			"If you want to disable the USB backend, set WITH_USB_BACKEND=OFF.")
+	else()
+		message(STATUS "Looking for libusb-1.0 : Found")
 
-	if(WITH_USB_BACKEND)
 		set(IIOD_CLIENT 1)
 		set(NEED_LIBXML2 1)
 		set(NEED_THREADS 1)
@@ -168,13 +161,10 @@ if (LIBUSB_LIBRARIES AND LIBUSB_INCLUDE_DIR)
 		set(TEMP1 ${CMAKE_REQUIRED_INCLUDES})
 		list(APPEND CMAKE_REQUIRED_LIBRARIES ${LIBUSB_LIBRARIES})
 		list(APPEND CMAKE_REQUIRED_INCLUDES ${LIBUSB_INCLUDE_DIR})
-		check_symbol_exists(libusb_get_version libusb.h
-				HAS_LIBUSB_GETVERSION)
+		check_symbol_exists(libusb_get_version libusb.h HAS_LIBUSB_GETVERSION)
 		set(CMAKE_REQUIRED_LIBRARIES ${TEMP})
-			set(CMAKE_REQUIRED_INCLUDES ${TEMP1})
+		set(CMAKE_REQUIRED_INCLUDES ${TEMP1})
 	endif()
-else()
-	message(STATUS "Looking for libusb-1.0 : Failed; building without usb")
 endif()
 
 # make sure all check_symbol_exists are before this point, otherwise they fail
@@ -260,31 +250,31 @@ if(WITH_LOCAL_BACKEND)
 	endif()
 endif()
 
-find_library(LIBSERIALPORT_LIBRARIES serialport)
-find_path(LIBSERIALPORT_INCLUDE_DIR libserialport.h)
-if (LIBSERIALPORT_LIBRARIES AND LIBSERIALPORT_INCLUDE_DIR)
-	option(WITH_SERIAL_BACKEND "Enable the serial backend" ON)
+option(WITH_SERIAL_BACKEND "Enable the serial backend" ON)
+if (WITH_SERIAL_BACKEND)
+	find_library(LIBSERIALPORT_LIBRARIES serialport)
+	find_path(LIBSERIALPORT_INCLUDE_DIR libserialport.h)
+	if (NOT LIBSERIALPORT_LIBRARIES OR NOT LIBSERIALPORT_INCLUDE_DIR)
+		message(SEND_ERROR "Unable to find libserialport dependency.\n"
+			"If you want to disable the serial backend, set WITH_SERIAL_BACKEND=OFF.")
+	else()
+		message(STATUS "Looking for libserialport : Found")
 
-	if (WITH_SERIAL_BACKEND)
 		file(STRINGS ${LIBSERIALPORT_INCLUDE_DIR}/libserialport.h LIBSERIALPORT_VERSION_STR REGEX "SP_PACKAGE_VERSION_STRING")
 		string(REGEX REPLACE "#define SP_PACKAGE_VERSION_STRING \"(.*)\"" "\\1" LIBSERIALPORT_VERSION ${LIBSERIALPORT_VERSION_STR})
 		if ("${LIBSERIALPORT_VERSION}" VERSION_LESS 0.1.1)
-			message(WARNING "The installed version of libserialport is too old. The minimum version supported is 0.1.1. Disabling Serial support.")
-			SET(WITH_SERIAL_BACKEND OFF)
-		else()
-			message(STATUS "Looking for libserialport : Found")
-			list(APPEND LIBIIO_CFILES serial.c)
-			list(APPEND LIBS_TO_LINK ${LIBSERIALPORT_LIBRARIES})
-
-			set(NEED_THREADS 1)
-			set(IIOD_CLIENT 1)
-			set(NEED_LIBXML2 1)
-
-			include_directories(${LIBSERIALPORT_INCLUDE_DIR})
+			message(SEND_ERROR "The installed version of libserialport is too old. The minimum version supported is 0.1.1.")
 		endif()
+
+		list(APPEND LIBIIO_CFILES serial.c)
+		list(APPEND LIBS_TO_LINK ${LIBSERIALPORT_LIBRARIES})
+
+		set(NEED_THREADS 1)
+		set(IIOD_CLIENT 1)
+		set(NEED_LIBXML2 1)
+
+		include_directories(${LIBSERIALPORT_INCLUDE_DIR})
 	endif()
-else()
-	message(STATUS "Looking for libserialport : Failed; building without serial")
 endif()
 
 option(WITH_ZSTD "Support for ZSTD compressed metadata" OFF)
@@ -293,7 +283,8 @@ if (WITH_ZSTD)
 	find_path(LIBZSTD_INCLUDE_DIR zstd.h)
 
 	if (NOT LIBZSTD_LIBRARIES OR NOT LIBZSTD_INCLUDE_DIR)
-		message(SEND_ERROR "Unable to find libzstd")
+		message(SEND_ERROR "Unable to find libzstd dependency.\n"
+			"If you want to disable ZSTD compression support, set WITH_ZSTD=OFF.")
 	endif()
 
 	list(APPEND LIBS_TO_LINK ${LIBZSTD_LIBRARIES})
@@ -309,12 +300,15 @@ if(WITH_NETWORK_BACKEND)
 	endif()
 
 	if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
-		include(CheckCSourceCompiles)
-		check_c_source_compiles("#include <fcntl.h>\nint main(void) { return O_TMPFILE; }" HAS_O_TMPFILE)
-
-		if (HAS_O_TMPFILE)
-			option(WITH_NETWORK_GET_BUFFER "Enable experimental zero-copy transfers" OFF)
-		endif(HAS_O_TMPFILE)
+		option(WITH_NETWORK_GET_BUFFER "Enable experimental zero-copy transfers" OFF)
+		if (WITH_NETWORK_GET_BUFFER)
+			include(CheckCSourceCompiles)
+			check_c_source_compiles("#include <fcntl.h>\nint main(void) { return O_TMPFILE; }" HAS_O_TMPFILE)
+
+			if (NOT HAS_O_TMPFILE)
+				message(SEND_ERROR "Zero-copy requires the O_TMPFILE flag, which is not available on the system.")
+			endif()
+		endif()
 
 		check_c_source_compiles("#include <sys/eventfd.h>\nint main(void) { return eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK); }" WITH_NETWORK_EVENTFD)
 	endif()
@@ -331,34 +325,37 @@ if(WITH_NETWORK_BACKEND)
 		list(APPEND LIBIIO_CFILES network-unix.c)
 	endif()
 
-	find_library(AVAHI_CLIENT_LIBRARIES avahi-client)
-	find_library(AVAHI_COMMON_LIBRARIES avahi-common)
-	if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+	option(HAVE_DNS_SD "Enable DNS-SD (ZeroConf) support" ON)
+	if (NOT HAVE_DNS_SD)
+		message(STATUS "Building without DNS-SD (ZeroConf) support")
+	elseif(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
 		find_library(CORE_SERVICES CoreServices)
 
 		message(STATUS "Building with CFNetServices, an Apple DNS SD implementation")
-		set(HAVE_DNS_SD ON)
 
 		list(APPEND LIBIIO_CFILES dns_sd_bonjour.c dns_sd.c)
 		list(APPEND LIBS_TO_LINK ${CORE_SERVICES} )
 
-	elseif(AVAHI_CLIENT_LIBRARIES AND AVAHI_COMMON_LIBRARIES)
-		message(STATUS "Building with Avahi, a DNS SD implementation")
-		set(HAVE_DNS_SD ON)
-		set(HAVE_AVAHI ON)
-		
-		list(APPEND LIBIIO_CFILES dns_sd_avahi.c dns_sd.c)
-		set(AVAHI_LIBRARIES ${AVAHI_CLIENT_LIBRARIES} ${AVAHI_COMMON_LIBRARIES})
-		list(APPEND LIBS_TO_LINK ${AVAHI_LIBRARIES})
 	elseif(WIN32)
-		set(HAVE_DNS_SD ON)
 		list(APPEND LIBIIO_CFILES dns_sd_windows.c dns_sd.c)
 		if (CMAKE_COMPILER_IS_GNUCC OR CMAKE_C_COMPILER_ID STREQUAL "Clang")
 			set_source_files_properties(dns_sd_windows.c PROPERTIES COMPILE_FLAGS "-Wno-unused-function")
 		endif()
 		message(STATUS "Building with mdns, A Public domain mDNS/DNS-SD library in C ")
 	else()
-		message(STATUS "Building without DNS-SD (Zeroconf) support")
+		find_library(AVAHI_CLIENT_LIBRARIES avahi-client)
+		find_library(AVAHI_COMMON_LIBRARIES avahi-common)
+		if (NOT AVAHI_CLIENT_LIBRARIES OR NOT AVAHI_COMMON_LIBRARIES)
+			message(SEND_ERROR "Unable to find libavahi-common / libavahi-client dependencies.\n"
+				"If you want to disable DNS-SD (ZeroConf) support, set HAVE_DNS_SD=OFF.")
+		endif()
+
+		message(STATUS "Building with Avahi, a DNS-SD (ZeroConf) implementation")
+		set(HAVE_AVAHI ON)
+
+		list(APPEND LIBIIO_CFILES dns_sd_avahi.c dns_sd.c)
+		set(AVAHI_LIBRARIES ${AVAHI_CLIENT_LIBRARIES} ${AVAHI_COMMON_LIBRARIES})
+		list(APPEND LIBS_TO_LINK ${AVAHI_LIBRARIES})
 	endif()
 
 	set(NEED_THREADS 1)
@@ -368,42 +365,47 @@ else()
 	message(STATUS "Building without network support")
 endif()
 
-# Since libxml2-2.9.2, libxml2 provides its own LibXml2-config.cmake, with all
-# variables correctly set.
-# So, try first to find the CMake module provided by libxml2 package, then fallback
-# on the CMake's FindLibXml2.cmake module (which can lack some definition, especially
-# in static build case).
-find_package(LibXml2 QUIET NO_MODULE)
-if(DEFINED LIBXML2_VERSION_STRING)
-	set(LIBXML2_FOUND ON)
-	set(LIBXML2_INCLUDE_DIR ${LIBXML2_INCLUDE_DIRS})
-else()
-	include(FindLibXml2)
-endif()
-
-if (LIBXML2_FOUND)
-	option(WITH_XML_BACKEND "Enable the XML backend" ON)
 
-	if (WITH_XML_BACKEND)
-		list(APPEND LIBIIO_CFILES xml.c)
+option(WITH_XML_BACKEND "Enable the XML backend" ON)
+if (WITH_XML_BACKEND)
+	# Since libxml2-2.9.2, libxml2 provides its own LibXml2-config.cmake, with all
+	# variables correctly set.
+	# So, try first to find the CMake module provided by libxml2 package, then fallback
+	# on the CMake's FindLibXml2.cmake module (which can lack some definition, especially
+	# in static build case).
+	find_package(LibXml2 QUIET NO_MODULE)
+	if(DEFINED LIBXML2_VERSION_STRING)
+		set(LIBXML2_FOUND ON)
+		set(LIBXML2_INCLUDE_DIR ${LIBXML2_INCLUDE_DIRS})
+	else()
+		include(FindLibXml2)
+	endif()
 
-		include_directories(${LIBXML2_INCLUDE_DIR})
-		list(APPEND LIBS_TO_LINK ${LIBXML2_LIBRARIES})
+	if (NOT LIBXML2_FOUND)
+		message(SEND_ERROR "Unable to find libxml2 dependency.\n"
+			"If you want to disable the XML backend, set WITH_XML_BACKEND=OFF.")
 	endif()
-endif()
 
-if (NEED_LIBXML2 AND NOT (LIBXML2_FOUND AND WITH_XML_BACKEND))
-	message(SEND_ERROR "The selected backends require libxml2 and the XML backend to be enabled")
+	list(APPEND LIBIIO_CFILES xml.c)
+
+	include_directories(${LIBXML2_INCLUDE_DIR})
+	list(APPEND LIBS_TO_LINK ${LIBXML2_LIBRARIES})
+elseif(NEED_LIBXML2)
+	message(SEND_ERROR "Enabled backends require the XML backend to be enabled as well.\n"
+		"If you want to enable the XML backend, set WITH_XML_BACKEND=ON.")
 endif()
 
-if (NEED_THREADS)
+option(NO_THREADS "Disable multi-threading support" OFF)
+if (NEED_THREADS AND NOT NO_THREADS)
 	if (NOT WIN32)
-		if (PTHREAD_LIBRARIES)
-			list(APPEND LIBS_TO_LINK ${PTHREAD_LIBRARIES})
-		else()
-			message(WARNING "pthread library not found; support for threads will be disabled")
-			set(NO_THREADS ON)
+		find_library(PTHREAD_LIBRARIES pthread)
+
+		if (NOT PTHREAD_LIBRARIES)
+			message(SEND_ERROR "Unable to find pthread dependency.\n"
+				"If you want to disable multi-threading support, set NO_THREADS=ON.")
 		endif()
+
+		list(APPEND LIBS_TO_LINK ${PTHREAD_LIBRARIES})
 	endif()
 
 	list(APPEND LIBIIO_CFILES lock.c)
@@ -577,8 +579,8 @@ if(WITH_IIOD)
 	set(UPSTART_CONF_INSTALL_DIR /etc/init CACHE PATH "default install path for upstart conf files")
 
 	if (NOT PTHREAD_LIBRARIES)
-		message(WARNING "IIOD requires threads support; disabling")
-		set(WITH_IIOD OFF CACHE BOOL "" FORCE)
+		message(SEND_ERROR "IIOD requires pthread support\n."
+			"If you want to disable IIOD, set WITH_IIOD=OFF.")
 	else()
 		add_subdirectory(iiod)
 	endif()
diff --git a/iio-config.h.cmakein b/iio-config.h.cmakein
index 39a9c73bc..781bfb6cc 100644
--- a/iio-config.h.cmakein
+++ b/iio-config.h.cmakein
@@ -17,9 +17,9 @@
 #cmakedefine01 WITH_NETWORK_EVENTFD
 #cmakedefine01 WITH_IIOD_USBD
 #cmakedefine01 WITH_LOCAL_CONFIG
+#cmakedefine01 WITH_AIO
 #cmakedefine01 HAVE_DNS_SD
 #cmakedefine01 HAVE_AVAHI
-#cmakedefine01 ENABLE_AIO
 #cmakedefine01 WITH_ZSTD
 
 #cmakedefine HAS_PIPE2
diff --git a/iiod/CMakeLists.txt b/iiod/CMakeLists.txt
index 22b699d5e..b91f00141 100644
--- a/iiod/CMakeLists.txt
+++ b/iiod/CMakeLists.txt
@@ -12,6 +12,13 @@ add_flex_bison_dependency(lexer parser)
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
 include_directories(${CMAKE_CURRENT_SOURCE_DIR})
 
+include(CheckSymbolExists)
+set(CMAKE_REQUIRED_LIBRARIES ${PTHREAD_LIBRARIES})
+set(CMAKE_REQUIRED_DEFINITIONS -D_GNU_SOURCE)
+check_symbol_exists(pthread_setname_np "pthread.h" HAS_PTHREAD_SETNAME_NP)
+set(CMAKE_REQUIRED_LIBRARIES)
+set(CMAKE_REQUIRED_DEFINITIONS)
+
 if (CMAKE_C_COMPILER_ID STREQUAL "Clang" OR CMAKE_COMPILER_IS_GNUCC)
 	# flex sometimes generates code which generate sign comparison errors
 	set_source_files_properties(${FLEX_lexer_OUTPUTS} PROPERTIES COMPILE_FLAGS "-Wno-sign-compare")
@@ -20,29 +27,33 @@ endif ()
 
 set(IIOD_CFILES iiod.c ops.c thread-pool.c ${BISON_parser_OUTPUTS} ${FLEX_lexer_OUTPUTS})
 
-find_library(LIBAIO_LIBRARIES aio)
-find_path(LIBAIO_INCLUDE_DIR libaio.h)
-
-if (LIBAIO_LIBRARIES AND LIBAIO_INCLUDE_DIR)
-	option(ENABLE_AIO "Build IIOD with async. I/O support" ON)
-endif ()
+option(WITH_AIO "Build IIOD with async. I/O support" ON)
+if (WITH_AIO)
+	find_library(LIBAIO_LIBRARIES aio)
+	find_path(LIBAIO_INCLUDE_DIR libaio.h)
 
-include(CheckTypeSize)
-set(CMAKE_EXTRA_INCLUDE_FILES linux/usb/functionfs.h)
-check_type_size("struct usb_functionfs_descs_head_v2" FUNCTIONFS_V2)
-set(CMAKE_EXTRA_INCLUDE_FILES)
+	if (NOT LIBAIO_LIBRARIES OR NOT LIBAIO_INCLUDE_DIR)
+		message(SEND_ERROR "Unable to find libaio dependency.\n"
+			"If you want to disable async. I/O support, set WITH_AIO=OFF.")
+	endif ()
 
-if (HAVE_FUNCTIONFS_V2)
-	OPTION(WITH_IIOD_USBD "Add support for USB through FunctionFS within IIOD" ${ENABLE_AIO})
+	message(STATUS "Looking for libaio: Found")
 
+	option(WITH_IIOD_USBD "Add support for USB through FunctionFS within IIOD" ON)
 	if (WITH_IIOD_USBD)
-		if (NOT ENABLE_AIO)
-			message(SEND_ERROR "USB support in IIOD requires async. I/O support")
-		endif (NOT ENABLE_AIO)
+		include(CheckTypeSize)
+		set(CMAKE_EXTRA_INCLUDE_FILES linux/usb/functionfs.h)
+		check_type_size("struct usb_functionfs_descs_head_v2" FUNCTIONFS_V2)
+		set(CMAKE_EXTRA_INCLUDE_FILES)
+
+		if (NOT HAVE_FUNCTIONFS_V2)
+			message(SEND_ERROR "Linux kernel headers are too old.\n"
+				"If you want to disable USB support, set WITH_IIOD_USBD=OFF.")
+		endif()
 
 		set(IIOD_CFILES ${IIOD_CFILES} usbd.c)
-	endif (WITH_IIOD_USBD)
-endif (HAVE_FUNCTIONFS_V2)
+	endif()
+endif()
 
 add_executable(iiod ${IIOD_CFILES})
 set_target_properties(iiod PROPERTIES
@@ -52,8 +63,7 @@ set_target_properties(iiod PROPERTIES
 )
 target_link_libraries(iiod iio ${PTHREAD_LIBRARIES} ${AVAHI_LIBRARIES})
 
-if (ENABLE_AIO)
-	add_definitions(-DWITH_AIO=1)
+if (WITH_AIO)
 	include_directories(${LIBAIO_INCLUDE_DIR})
 	target_link_libraries(iiod ${LIBAIO_LIBRARIES})
 endif ()
diff --git a/iiod/iiod.c b/iiod/iiod.c
index b4dc3d889..178558b90 100644
--- a/iiod/iiod.c
+++ b/iiod/iiod.c
@@ -373,7 +373,7 @@ int main(int argc, char **argv)
 			interactive = true;
 			break;
 		case 'a':
-			if (!ENABLE_AIO) {
+			if (!WITH_AIO) {
 				IIO_ERROR("IIOD was not compiled with AIO support.\n");
 				return EXIT_FAILURE;
 			}
diff --git a/network-unix.c b/network-unix.c
index 071f34b19..594ffc877 100644
--- a/network-unix.c
+++ b/network-unix.c
@@ -17,6 +17,7 @@
 #include <poll.h>
 #include <string.h>
 #include <sys/socket.h>
+#include <sys/time.h>
 #include <unistd.h>
 
 int set_blocking_mode(int fd, bool blocking)
diff --git a/network.c b/network.c
index 5ae9b2b18..1ed580302 100644
--- a/network.c
+++ b/network.c
@@ -23,6 +23,14 @@
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #else
+/*
+ * Old OSes (CentOS 7, Ubuntu 16.04) require this for the
+ * IN6_IS_ADDR_LINKLOCAL() macro to work.
+ */
+#define __USE_MISC
+#include <netinet/in.h>
+#undef __USE_MISC
+
 #include <arpa/inet.h>
 #include <netdb.h>
 #include <net/if.h>