--- a/config/autoconf.mk.in
+++ b/config/autoconf.mk.in
@@ -261,16 +261,18 @@ OS_LDFLAGS	= @LDFLAGS@
 
 OS_COMPILE_CFLAGS = $(OS_CPPFLAGS) @COMPILE_CFLAGS@
 OS_COMPILE_CXXFLAGS = $(OS_CPPFLAGS) @COMPILE_CXXFLAGS@
 
 OS_INCLUDES	= $(NSPR_CFLAGS) $(JPEG_CFLAGS) $(PNG_CFLAGS) $(ZLIB_CFLAGS) $(LCMS_CFLAGS)
 OS_LIBS		= @LIBS@
 ACDEFINES	= @MOZ_DEFINES@
 
+WARNINGS_AS_ERRORS = @WARNINGS_AS_ERRORS@
+
 MOZ_OPTIMIZE	= @MOZ_OPTIMIZE@
 MOZ_OPTIMIZE_FLAGS = @MOZ_OPTIMIZE_FLAGS@
 MOZ_OPTIMIZE_LDFLAGS = @MOZ_OPTIMIZE_LDFLAGS@
 
 MOZ_RTTI_FLAGS_ON = @_MOZ_RTTI_FLAGS_ON@
 
 PROFILE_GEN_CFLAGS = @PROFILE_GEN_CFLAGS@
 PROFILE_USE_CFLAGS = @PROFILE_USE_CFLAGS@

--- a/configure.in
+++ b/configure.in
@@ -1209,16 +1209,17 @@ dnl ====================================
 if test "$GNU_CC"; then
     MKSHLIB='$(CXX) $(CXXFLAGS) $(DSO_PIC_CFLAGS) $(DSO_LDOPTS) -Wl,-h,$@ -o $@'
     MKCSHLIB='$(CC) $(CFLAGS) $(DSO_PIC_CFLAGS) $(DSO_LDOPTS) -Wl,-h,$@ -o $@'
     DSO_LDOPTS='-shared'
     if test "$GCC_USE_GNU_LD"; then
         # Don't allow undefined symbols in libraries
         DSO_LDOPTS="$DSO_LDOPTS -Wl,-z,defs"
     fi
+    WARNINGS_AS_ERRORS='-Werror'
     DSO_CFLAGS=''
     DSO_PIC_CFLAGS='-fPIC'
     _MOZ_RTTI_FLAGS_ON=${_COMPILER_PREFIX}-frtti
     _MOZ_RTTI_FLAGS_OFF=${_COMPILER_PREFIX}-fno-rtti
     _MOZ_EXCEPTIONS_FLAGS_ON='-fhandle-exceptions'
     _MOZ_EXCEPTIONS_FLAGS_OFF='-fno-handle-exceptions'
 
     # Turn on GNU specific features
@@ -1729,16 +1730,17 @@ case "$target" in
     SYSTEM_MAKEDEPEND=
 
     HOST_CC=cl
     HOST_CXX=cl
     HOST_LD=link
     HOST_AR='lib -OUT:$@'
     HOST_RANLIB='echo ranlib'
         
+    WARNINGS_AS_ERRORS='/WX'
 	MOZ_OPTIMIZE_FLAGS='-O1'
     AR_FLAGS='-NOLOGO -OUT:"$@"'
     ASM_SUFFIX=asm
     CFLAGS="$CFLAGS -W3 -Gy -Fd\$(PDBFILE)"
     CXXFLAGS="$CXXFLAGS -W3 -Gy -Fd\$(PDBFILE)"
     DLL_PREFIX=
     DOXYGEN=:
     DSO_LDOPTS=-SUBSYSTEM:WINDOWSCE
@@ -1754,17 +1756,16 @@ case "$target" in
     MKSHLIB_FORCE_ALL=
     MKSHLIB_UNFORCE_ALL=
     MOZ_COMPONENT_NSPR_LIBS='$(NSPR_LIBS)'
     MOZ_COMPONENT_NSPR_LIBS='$(NSPR_LIBS)'
     MOZ_DEBUG_FLAGS='-Zi'
     MOZ_DEBUG_LDFLAGS='-DEBUG -DEBUGTYPE:CV'
     MOZ_FIX_LINK_PATHS=
     MOZ_JS_LIBS='$(LIBXUL_DIST)/lib/js$(MOZ_BITS)$(VERSION_NUMBER).lib'
-    MOZ_OPTIMIZE_FLAGS='-O1'
     MOZ_XPCOM_OBSOLETE_LIBS='$(LIBXUL_DIST)/lib/xpcom_compat.lib'
     OBJ_SUFFIX=obj
     RANLIB='echo not_ranlib'
     STRIP='echo not_strip'
     TARGET_NSPR_MDCPUCFG='\"md/_wince.cfg\"'
     UNZIP=unzip
     XARGS=xargs
     XPCOM_FROZEN_LDOPTS='$(LIBXUL_DIST)/lib/xpcom.lib'
@@ -1846,16 +1847,17 @@ case "$target" in
         MKSHLIB_FORCE_ALL=
         MKSHLIB_UNFORCE_ALL=
         DSO_LDOPTS=-SUBSYSTEM:WINDOWS
         CFLAGS="$CFLAGS -W3 -Gy -Fd\$(PDBFILE)"
         CXXFLAGS="$CXXFLAGS -W3 -Gy -Fd\$(PDBFILE)"
         LIBS="$LIBS kernel32.lib user32.lib gdi32.lib winmm.lib wsock32.lib advapi32.lib"
         MOZ_DEBUG_FLAGS='-Zi'
         MOZ_DEBUG_LDFLAGS='-DEBUG -DEBUGTYPE:CV'
+        WARNINGS_AS_ERRORS='/WX'
     	MOZ_OPTIMIZE_FLAGS='-O1'
         MOZ_JS_LIBS='$(LIBXUL_DIST)/lib/js$(MOZ_BITS)$(VERSION_NUMBER).lib'
         MOZ_FIX_LINK_PATHS=
         DYNAMIC_XPCOM_LIBS='$(LIBXUL_DIST)/lib/xpcom.lib $(LIBXUL_DIST)/lib/xpcom_core.lib'
         XPCOM_FROZEN_LDOPTS='$(LIBXUL_DIST)/lib/xpcom.lib'
         LIBXUL_LIBS='$(LIBXUL_DIST)/lib/xpcom.lib $(LIBXUL_DIST)/lib/xul.lib'
         MOZ_COMPONENT_NSPR_LIBS='$(NSPR_LIBS)'
         MOZ_XPCOM_OBSOLETE_LIBS='$(LIBXUL_DIST)/lib/xpcom_compat.lib'
@@ -2037,16 +2039,17 @@ case "$target" in
     MKCSHLIB='$(CC) $(CFLAGS) $(DSO_PIC_CFLAGS) $(DSO_LDOPTS) -Wl,-soname,lib$(LIBRARY_NAME)$(DLL_SUFFIX) -o $@'
     ;;
 
 *-nto*) 
 	AC_DEFINE(NTO)	
 	AC_DEFINE(_QNX_SOURCE)
 	AC_DEFINE(_i386)
 	OS_TARGET=NTO
+	WARNINGS_AS_ERRORS=''
 	MOZ_OPTIMIZE_FLAGS="-O"
 	MOZ_DEBUG_FLAGS="-gstabs"
 	USE_PTHREADS=1
 	_PEDANTIC=
 	LIBS="$LIBS -lsocket -lstdc++"
 	_DEFINES_CFLAGS='-Wp,-include -Wp,$(DEPTH)/mozilla-config.h -DMOZILLA_CLIENT -D_POSIX_C_SOURCE=199506'
 	_DEFINES_CXXFLAGS='-DMOZILLA_CLIENT -Wp,-include -Wp,$(DEPTH)/mozilla-config.h -D_POSIX_C_SOURCE=199506'
 	if test "$with_x" != "yes"
@@ -2131,16 +2134,17 @@ case "$target" in
         AR_FLAGS='r $@'
         CFLAGS="$CFLAGS -Zomf"
         CXXFLAGS="$CXXFLAGS -Zomf"
         DSO_LDOPTS='-Zdll'
         BIN_FLAGS='-Zlinker /ST:0x100000'
         IMPLIB='emximp -o'
         FILTER='emxexp -o'
         LDFLAGS='-Zmap'
+        WARNINGS_AS_ERRORS='-Werror'
         MOZ_DEBUG_FLAGS="-g -fno-inline"
         MOZ_OPTIMIZE_FLAGS="-O2 -s"
         MOZ_OPTIMIZE_LDFLAGS="-Zlinker /EXEPACK:2 -Zlinker /PACKCODE -Zlinker /PACKDATA"
         MOZ_XPCOM_OBSOLETE_LIBS='-L$(LIBXUL_DIST)/lib $(LIBXUL_DIST)/lib/xpcomct.lib'
         DYNAMIC_XPCOM_LIBS='-L$(LIBXUL_DIST)/lib $(LIBXUL_DIST)/lib/xpcom.lib $(LIBXUL_DIST)/lib/xpcomcor.lib'
         LIBXUL_LIBS='-L$(LIBXUL_DIST)/lib $(LIBXUL_DIST)/lib/xpcom.lib $(LIBXUL_DIST)/lib/xul.lib'
         if test -n "$MOZ_OS2_HIGH_MEMORY"; then
           DSO_LDOPTS="$DSO_LDOPTS -Zhigh-mem"
@@ -2176,16 +2180,17 @@ case "$target" in
         AS=alp
         ASFLAGS='-Mb'
         AS_DASH_C_FLAG=''
         ASM_SUFFIX=asm
         LD='-ilink'
         CFLAGS="/Q /qlibansi /Gm+ /Su4 /Mp /Tl9"
         CXXFLAGS="/Q /qlibansi /Gm+ /Su4 /Mp /Tl9 /Gx+"
         MOZ_DEBUG_FLAGS="/Ti+"
+        WARNINGS_AS_ERRORS='/WX'
         MOZ_OPTIMIZE_FLAGS="/O+ /Gl+ /G5 /qarch=pentium"
         LDFLAGS="/NOL /M"
         MOZ_DEBUG_LDFLAGS="/DE"
         MOZ_OPTIMIZE_LDFLAGS="/OPTFUNC /EXEPACK:2 /PACKCODE /PACKDATA"
         DSO_LDOPTS=''
         DSO_PIC_CFLAGS=
         IMPLIB='implib /NOL /NOI'
         FILTER='cppfilt -q -B -P'
@@ -2274,16 +2279,17 @@ dnl the qsort routine under solaris is f
        if test -z "$CROSS_COMPILE" && test -f /usr/lib/ld/map.noexstk; then
            _SAVE_LDFLAGS=$LDFLAGS
            LDFLAGS="-M /usr/lib/ld/map.noexstk $LDFLAGS" 
            AC_TRY_LINK([#include <stdio.h>],
                        [printf("Hello World\n");],
                        ,
                        [LDFLAGS=$_SAVE_LDFLAGS])
        fi
+       WARNINGS_AS_ERRORS='-Werror'
        MOZ_OPTIMIZE_FLAGS="-xO4"
        MKSHLIB='$(CXX) $(CXXFLAGS) $(DSO_PIC_FLAGS) $(DSO_LDOPTS) -h $@ -o $@'
        MKCSHLIB='$(CC) $(CFLAGS) $(DSO_PIC_FLAGS) -G -z muldefs -h $@ -o $@'
        MKSHLIB_FORCE_ALL='-z allextract'
        MKSHLIB_UNFORCE_ALL='-z defaultextract'
        DSO_LDOPTS='-G -z muldefs'
        AR_LIST="$AR t"
        AR_EXTRACT="$AR x"
@@ -7450,16 +7456,17 @@ AC_SUBST(MOZ_JS_LIBS)
 AC_SUBST(MOZ_PSM)
 AC_SUBST(MOZ_DEBUG)
 AC_SUBST(MOZ_DEBUG_MODULES)
 AC_SUBST(MOZ_PROFILE_MODULES)
 AC_SUBST(MOZ_DEBUG_ENABLE_DEFS)
 AC_SUBST(MOZ_DEBUG_DISABLE_DEFS)
 AC_SUBST(MOZ_DEBUG_FLAGS)
 AC_SUBST(MOZ_DEBUG_LDFLAGS)
+AC_SUBST(WARNINGS_AS_ERRORS)
 AC_SUBST(MOZ_DBGRINFO_MODULES)
 AC_SUBST(MOZ_EXTENSIONS)
 AC_SUBST(MOZ_IMG_DECODERS)
 AC_SUBST(MOZ_IMG_ENCODERS)
 AC_SUBST(MOZ_JSDEBUGGER)
 AC_SUBST(MOZ_OJI)
 AC_SUBST(MOZ_NO_XPCOM_OBSOLETE)
 AC_SUBST(MOZ_PLUGINS)

--- a/netwerk/cookie/src/Makefile.in
+++ b/netwerk/cookie/src/Makefile.in
@@ -55,9 +55,10 @@ REQUIRES	= \
 
 CPPSRCS		= \
 		nsCookie.cpp \
 		nsCookieService.cpp \
 		$(NULL)
 
 include $(topsrcdir)/config/rules.mk
 
+CXXFLAGS += $(WARNINGS_AS_ERRORS)
 DEFINES += -DIMPL_NS_NET