Line pattern in image mosaic when reprojecting

[ml.dje@…]

Creating a mosaic from seamless tiled images creates a regular pattern of lines
in the background color along the edges of the images. This only happens if the
image is requested in a projection other than the source projection.

Further:
1. only versions 4.8.x of mapserver are affected (4.6.1 works fine)
2. the pattern is only visible at certain combinations of image resolution, map
extent and map size.

Regarding 1: The gdal version is different (1.2 vs. 1.3). Maybe this is somehow
related.
Regarding 2: It seems that the effect preferably occurs if the images are scaled
down.

[ml.dje@…]

test case for the bug