Not really a clue but va_list is a variable argument list and on Solaris its a sore point w/ various added softwares. The va list thing isn't always well supported. I see a couple answers (google on "__need__va_list") suggesting not enough h2ph-ing e.g.:
"You need to run h2ph on your .h files. On a linux box, do this in /usr/include ..."
did you remember to h2ph the private gcc includes (generally in /usr/lib/gcc/.../include)

So, arch./OS related you may find this helps.

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