Add file that explains the libjpeg-turbo licenses

Previously this information was found in a page on libjpeg-turbo.org,
but there was still some confusion, because README-turbo.txt wasn't
clear as to which license applied to what.

Author: dcommander

LICENSE.txt

@@ -0,0 +1,79 @@
+libjpeg-turbo Licenses
+----------------------
+
+libjpeg-turbo is covered by three compatible BSD-style open source licenses:
+
+-- The IJG (Independent JPEG Group) License, which is listed in README
+
+   This license applies to the libjpeg API library and associated programs
+   (any code inherited from libjpeg, and any modifications to that code.)
+
+-- The Modified (3-clause) BSD License, which is listed in turbojpeg.c
+
+   This license covers the TurboJPEG API library and associated programs.
+
+-- The zlib License, which is listed in simd/jsimdext.inc
+
+   This license is a subset of the other two, and it covers the libjpeg-turbo
+   SIMD extensions.
+
+
+Complying with the libjpeg-turbo Licenses
+-----------------------------------------
+
+This section provides a roll-up of the libjpeg-turbo licensing terms, to the
+best of our understanding.
+
+1.  If you are distributing a modified version of the libjpeg-turbo source,
+    then:
+
+    a.  You cannot alter or remove any existing copyright or license notices
+        from the source.
+
+        Origin:  Clause 1 of the IJG License
+                 Clause 1 of the Modified BSD License
+                 Clauses 1 and 3 of the zlib License
+
+    b.  You must add your own copyright notice to the header of each source
+        file you modified, so others can tell that you modified that file (if
+        there is not an existing copyright header in that file, then you can
+        simply add a notice stating that you modified the file.)
+
+        Origin:  Clause 1 of the IJG License
+                 Clause 2 of the zlib License
+
+    c.  You must include the IJG README file, and you must not alter any of the
+        copyright or license text in that file.
+
+        Origin:  Clause 1 of the IJG License
+
+2.  If you are distributing only libjpeg-turbo binaries without the source, or
+    if you are distributing an application that statically links with
+    libjpeg-turbo, then:
+
+    a.  Your product documentation must include a message stating:
+
+        This software is based in part on the work of the Independent JPEG
+        Group.
+
+        Origin:  Clause 2 of the IJG license
+
+    b.  If your binary distribution includes or uses the TurboJPEG API, then
+        your product documentation must include the text of the Modified BSD
+        License.
+
+        Origin:  Clause 2 of the Modified BSD License
+
+3.  You cannot use the name of the IJG or The libjpeg-turbo Project or the
+    contributors thereof in advertising, publicity, etc.
+
+    Origin:  IJG License
+             Clause 3 of the Modified BSD License
+
+4.  The IJG and The libjpeg-turbo Project do not warrant libjpeg-turbo to be
+    free of defects, nor do we accept any liability for undesirable
+    consequences resulting from your use of the software.
+
+    Origin:  IJG License
+             Modified BSD License
+             zlib License

README-turbo.txt

@@ -28,33 +28,8 @@ broader range of users and developers.
 **     License
 *******************************************************************************
 
-Most of libjpeg-turbo inherits the non-restrictive, BSD-style license used by
-libjpeg (see README.)  The TurboJPEG wrapper (both C and Java versions) and
-associated test programs bear a similar license, which is reproduced below:
-
-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 in the documentation
-  and/or other materials provided with the distribution.
-- Neither the name of the libjpeg-turbo Project nor the names of its
-  contributors may be used to endorse or promote products derived from this
-  software without specific prior written permission.
-
-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 HOLDERS 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.
+libjpeg-turbo is covered by three compatible BSD-style open source licenses.
+Refer to LICENSE.txt for a roll-up of license terms.
 
 
 *******************************************************************************