Some tests might fail because the compiler should look in special
directories for some header files, or link against optional
-directories, or use special compilation options. You can force
+libraries, or use special compilation options. You can force
`configure' and the build process which follows it to do that by
setting the variables CPPFLAGS, CFLAGS, LDFLAGS, LIBS, and CC before
running `configure'. CPPFLAGS lists the options passed to the