add FITPACK Fortran library

start developing of FITPACK C++ bindings
mount_server.cpp: fix compilation error with GCC15

cxx/fitpack/fprota.f

@@ -0,0 +1,14 @@
+      recursive subroutine fprota(cos,sin,a,b)
+c  subroutine fprota applies a givens rotation to a and b.
+c  ..
+c  ..scalar arguments..
+      real*8 cos,sin,a,b
+c ..local scalars..
+      real*8 stor1,stor2
+c  ..
+      stor1 = a
+      stor2 = b
+      b = cos*stor2+sin*stor1
+      a = cos*stor1-sin*stor2
+      return
+      end