configure script disregards environment variable CC

[petrrr]

The script's help states the following:

Some influential environment variables:
  CC          C compiler command
  CFLAGS      C compiler flags
  LDFLAGS     linker flags, e.g. -L<lib dir> if you have libraries in a
              nonstandard directory <lib dir>
  LIBS        libraries to pass to the linker, e.g. -l<library>
  CPPFLAGS    (Objective) C/C++ preprocessor flags, e.g. -I<include dir> if
              you have headers in a nonstandard directory <include dir>

However, when I set the variable CC to a different compiler (clang), it still will disregard this setting and set it to /usr/bin/gcc. I am using this on a Mac OS X 10.8 system in the context of a package manager (MacPorts). I tested this with the 2.7 release.