Among the topics and files located here are solvers which focus on conventional linear algebra problems. There are ports to C from some of the routines in Linpack, and original solvers which are designed for high performance.
There is also a header file available. These C programs are functional equivalents to the FORTRAN versions, so grab your trusty Linpack manual for documentation and you're on your way. Note that Linpack relies on the BLAS for low level vector operations. In this port, the equivalent code is inserted directly into each routine.
These are ports from Algol to C. The differences in the languages are such that it is much easier to port from Algol to C than from FORTRAN to C.
Here is a set of Gaussian elimination routines for float, double and long double numeric types. A header file for these routines is here.