`png_icc_profile_error` is no longer used when writing iCCP chunks,
therefore it can be compiled out when the reading is disabled.
This change includes two `minconfig` files to test read-only and
write-only "full" configurations, to supplement the existing tests
for "minimal" configurations.
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
