diff --git a/submodules/build/iphone-config.site b/submodules/build/iphone-config.site
index 95812fc57..0b963c152 100644
--- a/submodules/build/iphone-config.site
+++ b/submodules/build/iphone-config.site
@@ -40,16 +40,17 @@ echo "Selecting SDK path = ${SYSROOT_PATH}"
 COMMON_FLAGS=" -arch ${ARCH} ${MCPU} -isysroot ${SYSROOT_PATH} -${CLANG_TARGET_SPECIFIER}=${SDK_VERSION} -DTARGET_OS_IPHONE=1 -D__IOS -fms-extensions"
 
 #workaround for polarssl conflicting symbols
-
 COMMON_FLAGS="$COMMON_FLAGS -Dsha256=polarssl_sha256"
 
+COMMON_FLAGS="$COMMON_FLAGS -Werror"
+
 # silence clang unused operators. This is temporary, we should find a way to compile 3rd party with correct flags :(
-COMMON_FLAGS="-Qunused-arguments -Wno-unknown-warning-option -Wno-unused-command-line-argument-hard-error-in-future $COMMON_FLAGS"
+COMMON_FLAGS="$COMMON_FLAGS -Qunused-arguments -Wno-unknown-warning-option -Wno-unused-command-line-argument-hard-error-in-future"
 
 # you can use ccache to speed up build, in which case just define LINPHONE_CCACHE to 'ccache'
 if test "$LINPHONE_CCACHE" = "ccache" ; then
 	# ccache doesn't like some options
-	COMMON_FLAGS="$COMMON_FLAGS -Wno-variadic-macros -Wno-pointer-arith -Wno-return-type -Wno-tautological-compare -Wno-unused-function -Wno-error"
+	COMMON_FLAGS="$COMMON_FLAGS -Wno-variadic-macros -Wno-pointer-arith -Wno-return-type -Wno-tautological-compare -Wno-unused-function"
 fi
 
 CC="xcrun $LINPHONE_CCACHE clang"
@@ -61,10 +62,11 @@ RANLIB="xcrun ranlib"
 STRIP="xcrun strip"
 NM="xcrun nm"
 
-LDFLAGS="-arch ${ARCH}"
-CFLAGS="$COMMON_FLAGS -std=c99"
-CPPFLAGS="$COMMON_FLAGS -Dasm=__asm"
-OBJCFLAGS="$COMMON_FLAGS -std=c99 -x objective-c -fexceptions -gdwarf-2 -fobjc-abi-version=2 -fobjc-legacy-dispatch"
+LDFLAGS="-arch ${ARCH}" #Linker flags
+CPPFLAGS="-Dasm=__asm" #C preprocessor flags
+CFLAGS="$COMMON_FLAGS -std=c99" #C flags
+CXXFLAGS="$COMMON_FLAGS" #C++ flags
+OBJCFLAGS="$COMMON_FLAGS -std=c99 -x objective-c -fexceptions -gdwarf-2 -fobjc-abi-version=2 -fobjc-legacy-dispatch" #ObjectiveC flags
 #Force install script to use -C so that header files don't get re-written if not changed.
 INSTALL_DATA="ginstall -C"