test: Add a few tests for obscure pnm formats

test/images/Makefile

@@ -43,6 +43,7 @@ imgs_64:  $(ALL_64)
  ALL_MISC += xeyes.jp2 xeyes.j2k
  ALL_MISC += xeyes-gray.png
  ALL_MISC += xeyes-gray.jp2 xeyes-gray.j2k
+ ALL_MISC += xeyes-P8.ppm
 imgs_misc: $(ALL_MISC)
 
 %.argb: %.png
@@ -99,6 +100,9 @@ imgs_misc: $(ALL_MISC)
 %-P3.ppm: %.ppm
 	pnmtopnm -plain <$< >$@
 
+%-P8.ppm: %.png
+	imlib2_conv $< $@
+
 %-P7_332.ppm: %.ppm
 	pamtoxvmini <$< >$@
 

test/test_load_2.cpp

@@ -60,6 +60,8 @@ static tii_t        tii[] = {
    { "icon-64-P3.ppm",		1153555547 },
    { "icon-64-P2.pgm",		 140949526 },
    { "icon-64-P1.pbm",		3936773892 },
+   { "icon-64-P7_332.ppm",	3790447752 },
+   { "xeyes-P8.ppm",		2937827957 },
    { "icon-64.tga",		1153555547 },
    { "icon-64.tiff",		1153555547 },
    { "icon-64.webp",		1698406918 },