Now that 1.0.0 has been released, I thought I would suggest fixing the linux header stuff, so that for instance the GNU Scientific Library (GSL) compiles; I think it would make a good test case.
For instance, the compilation of gsl-1.14 with the procedure
$ export CC="pcc"
$ export CPP="pcc -E"
libtool: compile: pcc -DHAVE_CONFIG_H -I. -I.. -I.. -DGSL_C99_INLINE -g -O2 -c hypot.c -fPIC -DPIC -o .libs/hypot.o
/usr/include/bits/mathinline.h, line 64: __l undefined
/usr/include/bits/mathinline.h, line 64: syntax error