Added license, read-me document

LICENSE

+Copyright (c) 2013 Lorenz Hüdepohl
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

README

+fdep
+----
+
+fdep is a small set of scripts to teach autoconf/automake (using GNU make)
+about the additional dependencies in Fortran 90 files due to modules.
+
+With this, Fortran files can be listed in any order in Makefile.am and parallel
+builds work.
+
+
+Usage
+-----
+
+  Put this project as a directory "fdep" in your sourcecode, place the two
+  lines
+
+    m4_include([fdep/fortran_dependencies.m4])
+    FDEP_F90_GNU_MAKE_DEPS
+
+  in your configure.ac, and add a single line
+
+    @FORTRAN_MODULE_DEPS@
+
+  in your Makefile.am. All .F90 files of all programs in bin_PROGRAMS will now
+  be scanned for modules and the resulting dependencies will be honoured.
+
+
+What is the problem with Fortran 90 modules and make dependencies?
+------------------------------------------------------------------
+
+  This set of three files can be used to tell a GNU make running an automake
+  produced Makefile about dependencies of Fortran 90 files with modules.
+
+  In Fortran 90 source files one can define any number of "modules", containing
+  variable and function definitions. The names of the modules defined in a file
+  can be arbitrary.
+
+  In another source file these modules can be used, informing the Fortran
+  compiler about the definitions in these modules (e.g. to do type-checking).
+  This creates a problem, as the compiler has to know somehow where the module
+  is defined.
+
+  The usual solution employed by almost every Fortran compiler is to create
+  special "module" files for each module contained in a source file during
+  compilation. Their file name is derived by a compiler-specific recipe of the
+  modules identifier (usually the lower-cased module's identifier plus ".mod",
+  so "foo_module.mod" and "some_other_module.mod"). When the compiler
+  encounters a "use" statement during the compilation of another file, it
+  confers to this file to import the definitions of the module.
+
+  That means, you cannot compile files using modules defined in yet uncompiled
+  files, one has to tell make about this dependency.
+
+  (A primitive solution to this problem is listing the file in a pre-sorted
+   order, so that files defining modules are compiled first.
+
+   However, the dependency-graph make knows about is incomplete and parallel
+   builds will fail with a high probability)
+
+
+How does fdep solve this problem technically?
+---------------------------------------------
+
+  As the name of the module files can be an arbitrary (and some compilers might
+  even save the module definitions in some completely different way), fdep
+  tells make about the module dependencies as a relation directly between
+  object files, e.g. when a file 'b.f90' is using any module of file 'a.f90',
+  fdep adds a dependency of
+
+    b.o: a.o
+
+
+  More specifically, the perl-script fortran_dependencies.pl is run by make to
+  create a file .fortran_modules/dependencies.mk, which is then included. To do
+  this, first every source file (for every program defined in bin_PROGRAMS) is
+  scanned for lines with "module" or "use" statements, which are saved in two
+  files (.use_mods and .def_mods) containing a list of defined and required
+  modules. The perl script then reads these in and produces the appropriate
+  rules.
+
+Drawbacks
+---------
+
+  GNU make is required. The detailed dependency graph due to "module" and "use"
+  statements is only available after pre-processing, when autoconf and even
+  configure is long over. To still get proper depdendencies, fdep uses the GNU
+  make feature to include a generated sub-Makefile during a make invocation.
+
+
+License
+-------
+
+  fdep is released under the MIT License. See the LICENSE file for details.
+
+
+Contributing
+------------
+
+  Send your patches or pull-request to dev@stellardeath.org

fortran_dependencies.m4

@@ -11,6 +11,9 @@ AC_MSG_RESULT([$_fdep_gnu_make_command])
 if test x$_fdep_gnu_make_command = x ; then
 	AC_MSG_ERROR([Need GNU Make])
 fi
-AC_SUBST([FORTRAN_MAKEFILE], ["include ${srcdir}/fdep/fortran_dependencies.mk"])
-AM_SUBST_NOTMAKE([FORTRAN_MAKEFILE])
+AC_SUBST([FORTRAN_MODULE_DEPS], ["
+CLEANFILES +=
+include ${srcdir}/fdep/fortran_dependencies.mk
+"])
+AM_SUBST_NOTMAKE([FORTRAN_MODULE_DEPS])
 ])

test_project/Makefile.am

@@ -17,5 +17,4 @@ test_baz_SOURCES = src2/baz.F90 src/bar.F90
 test_baz_CPPFLAGS = -DPROGRAM_test_baz
 test_baz_FCFLAGS = $(FC_MODOUT)$(_f90_moddir)/test_baz $(FC_MODINC)$(_f90_moddir)/test_baz
 
-CLEANFILES=
-@FORTRAN_MAKEFILE@
+@FORTRAN_MODULE_DEPS@