I want to use newlib instead of glibc because I work on cygwin. The github project I want to use uses glibc as default, because I'm on cygwin I cant use glibc, so I want to use newlib but I don't know how.
Not a solution, as we have no clue of your project, but more a general recipe of what need to be done as already mentioned by another comment.
Check on config.log more details on
configure: error: Could not use standard C library
If it is a generic Glibc test you can remove/change in a warning/comment the test in
configure.ac and than run autoreconf to rebuild configure
After that you run again configure and than chase and analyze any further error during the configure, build and test phases.
If it is not a generic glib test, but if it is a proper test of a C functionality you need to analyze what is the expected behavior and if Newlib can provide it in a alternate way.