Trouble building 21.4.22

[Alan Mackenzie]

Hello, XEmacs.

When I try to build XEmacs-21.4.22 on a fully normal Gnu/Linux system, I
get the following errors:

gcc -c -g -O3 -Wall -Wno-switch -Winline -Wmissing-prototypes -Wsign-compare -fno-strict-aliasing -Wshadow  -Demacs -I. -DHAVE_CONFIG_H glyphs-eimage.c
glyphs-eimage.c: In function 'png_instantiate':
glyphs-eimage.c:940:22: error: dereferencing pointer to incomplete type
glyphs-eimage.c:941:21: error: dereferencing pointer to incomplete type
glyphs-eimage.c:993:17: error: dereferencing pointer to incomplete type
glyphs-eimage.c:996:17: error: dereferencing pointer to incomplete type
glyphs-eimage.c:997:17: error: dereferencing pointer to incomplete type
glyphs-eimage.c:1000:17: error: dereferencing pointer to incomplete type
glyphs-eimage.c:1003:17: error: dereferencing pointer to incomplete type
glyphs-eimage.c:1006:17: error: dereferencing pointer to incomplete type
glyphs-eimage.c:1008:14: error: dereferencing pointer to incomplete type
make[1]: *** [glyphs-eimage.o] Error 1

This used to work fine.  I think I've upgraded GCC in the meantime.

Has anybody else seen this, or can anybody offer me any suggestions?

Thanks!

-- 
Alan Mackenzie (Nuremberg, Germany).