signbitl on powerpc-apple-darwin8.11.0

[Simon Josefsson]

Building gnulib (vasnprintf.c) on this platform (Mac OS X 10.4 fully
updated) results in:

/usr/libexec/gcc/powerpc-apple-darwin8/4.0.1/ld: Undefined symbols:
_signbitl
collect2: ld returned 1 exit status

Configure finds this:

configure:79962: checking for signbit macro
configure:80053: gcc -std=gnu99 -o conftest -g -O2 -I/opt/local/include  
conftest.c -lm    >&5
configure:80056: $? = 0
configure:80062: ./conftest
configure:80065: $? = 0
configure:80082: result: yes
configure:80084: checking for signbit compiler built-ins
configure:80169: gcc -std=gnu99 -o conftest -g -O2 -I/opt/local/include  
conftest.c -lm    >&5
configure:80172: $? = 0
configure:80178: ./conftest
configure:80181: $? = 0
configure:80198: result: yes

However, apparently, it doesn't work out well.

The system does appear to have __signbit? in its libc.

Ideas?

/Simon