Use fdep for proper Fortran module dependencies

This should enable parallel compilation

Makefile.am

@@ -116,3 +116,6 @@ install-exec-hook:
 # install .mod files (or whatever your compiler calls them) in $(includedir)
 install-data-hook:
 	cp modules/* $(DESTDIR)$(ftimings_includedir)/
+
+# use fdep
+@FORTRAN_MODULE_DEPS@

configure.ac

@@ -10,6 +10,9 @@ AM_INIT_AUTOMAKE([foreign -Wall -Werror])
 AM_SILENT_RULES([yes])
 m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
 
+m4_include([fdep/fortran_dependencies.m4])
+FDEP_F90_GNU_MAKE_DEPS
+
 AC_PROG_EGREP
 
 AC_LANG([Fortran])