The XSLT C library of Gnome (source files)
libxslt_source-1.1.34-4-source
Libxslt implements most of the EXSLT set of processor-portable extensions functions and some of Saxon's evaluate and expressions extensions.
People can either embed the library in their application or use xsltproc the command line processing tool. This library is free software and can be reused in commercial applications.