add Licensing information

Author: perazz

doc/specs/stdlib_linalg.md

@@ -61,6 +61,70 @@ or directly via compiler flags:
 {!example/linalg/example_lapack_getrf.f90!}
 ```
 
+### Licensing
+
+The Fortran Standard Library is distributed under the MIT License. `LAPACK` and its contained `BLAS` are a 
+freely-available software package. They are available from [netlib](https://www.netlib.org/lapack/) via anonymous 
+ftp and the World Wide Web. Thus, they can be included in commercial software packages (and have been). 
+The license used for the `BLAS` and `LAPACK` backends is the [modified BSD license](https://www.netlib.org/lapack/LICENSE.txt).
+
+The header of the `LICENSE.txt` file has as its licensing requirements:
+
+    Copyright (c) 1992-2013 The University of Tennessee and The University
+                            of Tennessee Research Foundation.  All rights
+                            reserved.
+    Copyright (c) 2000-2013 The University of California Berkeley. All
+                            rights reserved.
+    Copyright (c) 2006-2013 The University of Colorado Denver.  All rights
+                            reserved.
+
+    $COPYRIGHT$
+
+    Additional copyrights may follow
+
+    $HEADER$
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions are
+    met:
+
+    - Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    - Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer listed
+      in this license in the documentation and/or other materials
+      provided with the distribution.
+
+    - Neither the name of the copyright holders nor the names of its
+      contributors may be used to endorse or promote products derived from
+      this software without specific prior written permission.
+
+    The copyright holders provide no reassurances that the source code
+    provided does not infringe any patent, copyright, or any other
+    intellectual property rights of third parties.  The copyright holders
+    disclaim any liability to any recipient for claims brought against
+    recipient by any third party for infringement of that parties
+    intellectual property rights.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+So the license for the `LICENSE.txt` code is compatible with the use of
+modified versions of the code in the Fortran Standard Library under the MIT license.    
+Credit for the `BLAS`, `LAPACK` libraries should be given to the [LAPACK authors](https://www.netlib.org/lapack/contributor-list.html).
+According to the original license, we also changed the name of the routines and commented the changes made 
+to the original.
+    
 ## `diag` - Create a diagonal array or extract the diagonal elements of an array
 
 ### Status