diff --git a/mozilla/gfx/cairo/cairo/src/Makefile.in b/mozilla/gfx/cairo/cairo/src/Makefile.in
index c128e377a9e..73ac99860af 100644
--- a/mozilla/gfx/cairo/cairo/src/Makefile.in
+++ b/mozilla/gfx/cairo/cairo/src/Makefile.in
@@ -53,6 +53,17 @@ MODULE          = cairo
 LIBRARY_NAME    = mozcairo
 LIBXUL_LIBRARY = 1
 
+ifdef GNU_CC
+MODULE_OPTIMIZE_FLAGS = -O2
+else
+ifeq ($(OS_ARCH),SunOS)
+MODULE_OPTIMIZE_FLAGS = -fast
+endif
+ifeq ($(OS_ARCH),WINNT)
+MODULE_OPTIMIZE_FLAGS = -O2
+endif
+endif
+
 REQUIRES        = $(PNG_REQUIRES) \
                   $(ZLIB_REQUIRES) \
                   libpixman \
diff --git a/mozilla/gfx/cairo/libpixman/src/Makefile.in b/mozilla/gfx/cairo/libpixman/src/Makefile.in
index e0414d789f8..ff9a565efaa 100644
--- a/mozilla/gfx/cairo/libpixman/src/Makefile.in
+++ b/mozilla/gfx/cairo/libpixman/src/Makefile.in
@@ -51,6 +51,17 @@ ifndef MOZ_ENABLE_LIBXUL
 VISIBILITY_FLAGS =
 endif
 
+ifdef GNU_CC
+MODULE_OPTIMIZE_FLAGS = -O2
+else
+ifeq ($(OS_ARCH),SunOS)
+MODULE_OPTIMIZE_FLAGS = -fast
+endif
+ifeq ($(OS_ARCH),WINNT)
+MODULE_OPTIMIZE_FLAGS = -O2
+endif
+endif
+
 CSRCS	= \
 	fbcompose.c \
 	fbedge.c \