The GLX 1.0 license is non-free, and yet, it was in use in XFree86 and Xorg for many years. In 2008, SGI declared that GLX 2.0 was identical to the MIT license, and migrated all code owned by SGI to the GLX 2.0 license. (http://www.sgi.com/company_info/newsroom/press_releases/2008/september/opengl.html)
A copy of the GLX 1.0 is archived here, taken from http://web.archive.org/web/20061104002735/www.sgi.com/products/software/opensource/glx/glxlicense.txt on January 4, 2010.
GLX PUBLIC LICENSE (Version 1.0 (2/11/99)) ("License") Subject to any third party claims, Silicon Graphics, Inc. ("SGI") hereby grants permission to Recipient (defined below), under Recipient's copyrights in the Original Software (defined below), to use, copy, modify, merge, publish, distribute, sublicense and/or sell copies of Subject Software (defined below), and to permit persons to whom the Subject Software is furnished in accordance with this License to do the same, subject to all of the following terms and conditions, which Recipient accepts by engaging in any such use, copying, modifying, merging, publishing, distributing, sublicensing or selling: 1. Definitions. (a) "Original Software" means source code of computer software code which is described in Exhibit A as Original Software. (b) "Modifications" means any addition to or deletion from the substance or structure of either the Original Software or any previous Modifications. When Subject Software is released as a series of files, a Modification means (i) any addition to or deletion from the contents of a file containing Original Software or previous Modifications and (ii) any new file that contains any part of the Original Code or previous Modifications. (c) "Subject Software" means the Original Software or Modifications or the combination of the Original Software and Modifications, or portions of any of the foregoing. (d) "Recipient" means an individual or a legal entity exercising rights under, and complying with all of the terms of, this License. For legal entities, "Recipient" includes any entity which controls, is controlled by, or is under common control with Recipient. For purposes of this definition, "control" of an entity means (a) the power, direct or indirect, to direct or manage such entity, or (b) ownership of fifty percent (50%) or more of the outstanding shares or beneficial ownership of such entity. 2. Redistribution of Source Code Subject to These Terms. Redistributions of Subject Software in source code form must retain the notice set forth in Exhibit A, below, in every file. A copy of this License must be included in any documentation for such Subject Software where the recipients' rights relating to Subject Software are described. Recipient may distribute the source code version of Subject Software under a license of Recipient's choice, which may contain terms different from this License, provided that (i) Recipient is in compliance with the terms of this License, and (ii) the license terms include this Section 2 and Sections 3, 4, 7, 8, 10, 12 and 13 of this License, which terms may not be modified or superseded by any other terms of such license. If Recipient distributes the source code version under a different license Recipient must make it absolutely clear that any terms which differ from this License are offered by Recipient alone, not by SGI. Recipient hereby agrees to indemnify SGI for any liability incurred by SGI as a result of any such terms Recipient offers. 3. Redistribution in Executable Form. The notice set forth in Exhibit A must be conspicuously included in any notice in an executable version of Subject Software, related documentation or collateral in which Recipient describes the user's rights relating to the Subject Software. Recipient may distribute the executable version of Subject Software under a license of Recipient's choice, which may contain terms different from this License, provided that (i) Recipient is in compliance with the terms of this License, and (ii) the license terms include this Section 3 and Sections 4, 7, 8, 10, 12 and 13 of this License, which terms may not be modified or superseded by any other terms of such license. If Recipient distributes the executable version under a different license Recipient must make it absolutely clear that any terms which differ from this License are offered by Recipient alone, not by SGI. Recipient hereby agrees to indemnify SGI for any liability incurred by SGI as a result of any such terms Recipient offers. 4. Termination. This License and the rights granted hereunder will terminate automatically if Recipient fails to comply with terms herein and fails to cure such breach within 30 days of the breach. Any sublicense to the Subject Software which is properly granted shall survive any termination of this License absent termination by the terms of such sublicense. Provisions which, by their nature, must remain in effect beyond the termination of this License shall survive. 5. No Trademark Rights. This License does not grant any rights to use any trade name, trademark or service mark whatsoever. No trade name, trademark or service mark of SGI may be used to endorse or promote products derived from the Subject Software without prior written permission of SGI. 6. No Other Rights. This License does not grant any rights with respect to the OpenGL API or to any software or hardware implementation thereof or to any other software whatsoever, nor shall any other rights or licenses not expressly granted hereunder arise by implication, estoppel or otherwise with respect to the Subject Software. Title to and ownership of the Original Software at all times remains with SGI. All rights in the Original Software not expressly granted under this License are reserved. 7. Compliance with Laws; Non-Infringement. Recipient shall comply with all applicable laws and regulations in connection with use and distribution of the Subject Software, including but not limited to, all export and import control laws and regulations of the U.S. government and other countries. Recipient may not distribute Subject Software that (i) in any way infringes (directly or contributorily) the rights (including patent, copyright, trade secret, trademark or other intellectual property rights of any kind) of any other person or entity or (ii) breaches any representation or warranty, express, implied or statutory, which under any applicable law it might be deemed to have been distributed. 8. Claims of Infringement. If Recipient at any time has knowledge of any one or more third party claims that reproduction, modification, use, distribution, import or sale of Subject Software (including particular functionality or code incorporated in Subject Software) infringes the third party's intellectual property rights, Recipient must place in a well-identified web page bearing the title "LEGAL" a description of each such claim and a description of the party making each such claim in sufficient detail that a user of the Subject Software will know whom to contact regarding the claim. Also, upon gaining such knowledge of any such claim, Recipient must conspicuously include the URL for such web page in the Exhibit A notice required under Sections 2 and 3, above, and in the text of any related documentation, license agreement or collateral in which Recipient describes end user's rights relating to the Subject Software. If Recipient obtains such knowledge after it makes Subject Software available to any other person or entity, Recipient shall take other steps (such as notifying appropriate mailing lists or newsgroups) reasonably calculated to inform those who received the Subject Software that new knowledge has been obtained. 9. DISCLAIMER OF WARRANTY. SUBJECT SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES THAT THE SUBJECT SOFTWARE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE OR NON- INFRINGING. SGI ASSUMES NO RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE. SHOULD ANY SOFTWARE PROVE DEFECTIVE IN ANY RESPECT, SGI ASSUMES NO COST OR LIABILITY FOR ANY SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. NO USE OF ANY SUBJECT SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER THIS DISCLAIMER. 10. LIMITATION OF LIABILITY. UNDER NO CIRCUMSTANCES AND UNDER NO LEGAL THEORY, WHETHER TORT (INCLUDING, WITHOUT LIMITATION, NEGLIGENCE OR STRICT LIABILITY), CONTRACT, OR OTHERWISE, SHALL SGI OR ANY SGI LICENSOR BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OF ANY CHARACTER INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF GOODWILL, WORK STOPPAGE, LOSS OF DATA, COMPUTER FAILURE OR MALFUNCTION, OR ANY AND ALL OTHER COMMERCIAL DAMAGES OR LOSSES, EVEN IF SUCH PARTY SHALL HAVE BEEN INFORMED OF THE POSSIBILITY OF SUCH DAMAGES. THIS LIMITATION OF LIABILITY SHALL NOT APPLY TO LIABILITY FOR DEATH OR PERSONAL INJURY RESULTING FROM SGI's NEGLIGENCE TO THE EXTENT APPLICABLE LAW PROHIBITS SUCH LIMITATION. SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THAT EXCLUSION AND LIMITATION MAY NOT APPLY TO RECIPIENT. 11. Indemnity. Recipient shall be solely responsible for damages arising, directly or indirectly, out of its utilization of rights under this License. Recipient will defend, indemnify and hold harmless Silicon Graphics, Inc. from and against any loss, liability, damages, costs or expenses (including the payment of reasonable attorneys fees) arising out of Recipient's use, modification, reproduction and distribution of the Subject Software or out of any representation or warranty made by Recipient. 12. U.S. Government End Users. The Subject Software is a "commercial item" consisting of "commercial computer software" as such terms are defined in title 48 of the Code of Federal Regulations and all U.S. Government End Users acquire only the rights set forth in this License and are subject to the terms of this License. 13. Miscellaneous. This License represents the complete agreement concerning subject matter hereof. If any provision of this License is held to be unenforceable, such provision shall be reformed so as to achieve as nearly as possible the same economic effect as the original provision and the remainder of this License will remain in effect. This License shall be governed by and construed in accordance with the laws of the United States and the State of California as applied to agreements entered into and to be performed entirely within California between California residents. Any litigation relating to this License shall be subject to the exclusive jurisdiction of the Federal Courts of the Northern District of California (or, absent subject matter jurisdiction in such courts, the courts of the State of California), with venue lying exclusively in Santa Clara County, California, with the losing party responsible for costs, including without limitation, court costs and reasonable attorneys fees and expenses. The application of the United Nations Convention on Contracts for the International Sale of Goods is expressly excluded. Any law or regulation which provides that the language of a contract shall be construed against the drafter shall not apply to this License. Exhibit A The contents of this file are subject to Sections 2, 3, 4, 7, 8, 10, 12 and 13 of the GLX Public License Version 1.0 (the "License"). You may not use this file except in compliance with those sections of the License. You may obtain a copy of the License at Silicon Graphics, Inc., attn: Legal Services, 2011 N. Shoreline Blvd., Mountain View, CA 94043 or at http://www.sgi.com/software/opensource/glx/license.html. Software distributed under the License is distributed on an "AS IS" basis. ALL WARRANTIES ARE DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, OF FITNESS FOR A PARTICULAR PURPOSE OR OF NON- INFRINGEMENT. See the License for the specific language governing rights and limitations under the License. The Original Software is GLX version 1.2 source code, released February, 1999. The developer of the Original Software is Silicon Graphics, Inc. Those portions of the Subject Software created by Silicon Graphics, Inc. are Copyright (c) 1991-9 Silicon Graphics, Inc. All Rights Reserved.