Add -Wunsafe-loop-optimizations compiler flag and fix all warnings

configure.in

@@ -535,6 +535,7 @@ WARN_CFLAGS=""
 if test "x$GCC" = "xyes"; then
 	WARN_CFLAGS="-Wall -Wsign-compare -Werror-implicit-function-declaration \
 	-Wstrict-aliasing=2 -Wpointer-arith -Wwrite-strings -Winit-self \
+	-Wunsafe-loop-optimizations \
 	-Wpacked -Wmissing-format-attribute -Wstrict-prototypes \
 	-Wmissing-prototypes -Wmissing-declarations -Wdeclaration-after-statement \
 	-Wnested-externs -fno-strict-aliasing -Wold-style-definition"

pixman/src/fbmmx.c

@@ -1060,7 +1060,7 @@ fbCompositeSolidMask_nx8888x8888Cmmx (pixman_operator_t	op,
 
     while (height--)
     {
-	int twidth = width;
+	unsigned int twidth = width;
 	CARD32 *p = (CARD32 *)maskLine;
 	CARD32 *q = (CARD32 *)dstLine;
 
@@ -2020,7 +2020,7 @@ fbCompositeSolidMask_nx8888x0565Cmmx (pixman_operator_t      op,
 
     while (height--)
     {
-	int twidth = width;
+	unsigned int twidth = width;
 	CARD32 *p = (CARD32 *)maskLine;
 	CARD16 *q = (CARD16 *)dstLine;
 
@@ -2270,7 +2270,7 @@ fbSolidFillmmx (FbPixels	*pDraw,
 
     while (height--)
     {
-	int w;
+	unsigned int w;
 	CARD8 *d = byte_line;
 	byte_line += stride;
 	w = byte_width;
@@ -2386,7 +2386,7 @@ fbCopyAreammx (FbPixels	*pSrc,
 
     while (height--)
     {
-	int w;
+	unsigned int w;
 	CARD8 *s = src_bytes;
 	CARD8 *d = dst_bytes;
 	src_bytes += src_stride;

src/cairo-xlib-surface.c

@@ -2423,7 +2423,7 @@ _cairo_xlib_surface_add_glyph (Display *dpy,
 	break;
     case CAIRO_FORMAT_ARGB32:
 	if (_native_byte_order_lsb() != (ImageByteOrder (dpy) == LSBFirst)) {
-	    int		    c = glyph_surface->stride * glyph_surface->height;
+	    unsigned int    c = glyph_surface->stride * glyph_surface->height;
 	    unsigned char   *d;
 	    unsigned char   *new, *n;