interix: building graphics/netpbm failures

[Aleksey Cheusov <cheusov%tut.by@localhost>]

Hi all.
Can anybody explain why building the graphics/netpbm failures 
under Interix 3.5?

Error messages look like this
gcc -L/usr/pkg/lib -Wl,-R/usr/pkg/lib -o pnmtopng pnmtopng.o pngtxt.o \
          
`/dev/fs/P/usr/pkgsrc/graphics/netpbm/work/netpbm-10.34/buildtools/libopt 
/dev/fs/P/usr/pkgsrc/graphics/netpbm/work/netpbm-10.34/lib/libnetpbm.so  
/lib/libpng12.so /lib/libz.so` \
          -lm    
libopt results: ' -L/dev/fs/P/usr/pkgsrc/graphics/netpbm/work/netpbm-10.34/lib 
-lnetpbm -L/lib -lpng12 -L/lib -lz'
pnmtopng.o(.text+0xf13):pnmtopng.c: undefined reference to `_png_get_error_ptr'
pnmtopng.o(.text+0x2595):pnmtopng.c: undefined reference to 
`_png_set_compression_buffer_size'
pnmtopng.o(.text+0x25b5):pnmtopng.c: undefined reference to 
`_png_set_compression_level'
pnmtopng.o(.text+0x25ca):pnmtopng.c: undefined reference to 
`_png_set_compression_mem_level'
pnmtopng.o(.text+0x25df):pnmtopng.c: undefined reference to 
`_png_set_compression_strategy'
pnmtopng.o(.text+0x25f4):pnmtopng.c: undefined reference to 
`_png_set_compression_window_bits'
pnmtopng.o(.text+0x2609):pnmtopng.c: undefined reference to 
`_png_set_compression_method'
pnmtopn
...

Full log is here
http://home.duh.org/interix-pkgstat/20061127.1158/graphics/netpbm/.broken.html

Xxxx/libopt returns ... -lpng12 ...

Changing '-lpng12' with '-static -png12 -dynamic' fixes the problem,
but I don't understand why. Can anybody help and/or suggest/commit "right" fix?

According to bulk build log because of graphics/netpbm more than 800(!)
packages cannot be build.

-- 
Best regards, Aleksey Cheusov.