Add Farbfeld read only support

autotests/CMakeLists.txt

@@ -76,6 +76,7 @@ endmacro()
 # Loads each <format> image in read/<format>/, and compares the
 # result against the data read from the corresponding png file
 kimageformats_read_tests(
+    ff
     hdr
     iff
     pcx

autotests/ossfuzz/build_fuzzers.sh

@@ -162,6 +162,7 @@ HANDLER_TYPES="ANIHandler ani
         QAVIFHandler avif
         QDDSHandler dds
         EXRHandler exr
+        FFHandler ff
         HDRHandler hdr
         HEIFHandler heif
         IFFHandler iff

autotests/ossfuzz/kimgio_fuzzer.cc

@@ -23,7 +23,7 @@
   Usage:
     python infra/helper.py build_image kimageformats
     python infra/helper.py build_fuzzers --sanitizer undefined|address|memory kimageformats
-    python infra/helper.py run_fuzzer kimageformats kimgio_[ani|avif|dds|exr|hdr|heif|iff|jp2|jxl|jxr|kra|ora|pcx|pfm|pic|psd|pxr|qoi|ras|raw|rgb|sct|tim|tga|xcf]_fuzzer
+    python infra/helper.py run_fuzzer kimageformats kimgio_[ani|avif|dds|exr|ff|hdr|heif|iff|jp2|jxl|jxr|kra|ora|pcx|pfm|pic|psd|pxr|qoi|ras|raw|rgb|sct|tim|tga|xcf]_fuzzer
 */
 
 #include <QBuffer>
@@ -34,6 +34,7 @@
 #include "avif_p.h"
 #include "dds_p.h"
 #include "exr_p.h"
+#include "ff_p.h"
 #include "hdr_p.h"
 #include "heif_p.h"
 #include "iff_p.h"