EGLBE: Always expose GLX_EXT_framebuffer_sRGB

... regardless of which EGL API version the underlying EGL
implementation supports.  Referring to
9882331, sRGB rendering is required by
the OpenGL 3.0 spec.  We can't support GLX_ARB_create_context* with EGL
1.4- because eglCreateContext() lacks the necessary attributes, but
nothing prevents us from supporting GLX_EXT_framebuffer_sRGB with any
EGL API version.  (Making that extension contingent upon EGL 1.5 was an
error on my part when I authored
9882331.)  This is known to affect
VMware Linux guests.

This commit also modifies GLXspheres so that it only checks for the
existence of GLX_EXT_framebuffer_sRGB if -srgb is specified.

ChangeLog.md

@@ -44,6 +44,12 @@ had previously been initialized on the 2D X server without VirtualGL.
 other elements of the Firefox browser window to disappear when the window was
 resized.
 
+10. Fixed an issue in the EGL back end whereby `GLX_EXT_framebuffer_sRGB` was
+not added to the list of extensions returned by
+`glXGetClientString(..., GLX_EXTENSIONS)`, `glXQueryExtensionsString()`, or
+`glXQueryServerString(..., GLX_EXTENSIONS)` unless the underlying EGL
+implementation supported v1.5 or later of the EGL API.
+
 
 3.0.2
 =====

demos/glxspheres.c

@@ -587,7 +587,7 @@ int main(int argc, char **argv)
 		rgbAttribs[19] = 32 - bpc * 3;
 	}
 
-	if(!GLX_EXTENSION_EXISTS(GLX_EXT_framebuffer_sRGB))
+	if(useSRGB && !GLX_EXTENSION_EXISTS(GLX_EXT_framebuffer_sRGB))
 		THROW("GLX_EXT_framebuffer_sRGB extension is not available");
 
 	c = glXChooseFBConfig(dpy, screen, rgbAttribs, &n);

server/faker-glx.cpp

@@ -1,6 +1,6 @@
 // Copyright (C)2004 Landmark Graphics Corporation
 // Copyright (C)2005, 2006 Sun Microsystems, Inc.
-// Copyright (C)2009, 2011-2023 D. R. Commander
+// Copyright (C)2009, 2011-2024 D. R. Commander
 //
 // This library is free software and may be redistributed and/or modified under
 // the terms of the wxWindows Library License, Version 3.1 or (at your option)
@@ -866,7 +866,10 @@ static const char *getGLXExtensions(void)
 		if((faker::eglMajor > 1 || (faker::eglMajor == 1 && faker::eglMinor >= 5))
 			&& !strstr(glxextensions, "GLX_ARB_create_context"))
 			strncat(glxextensions,
-				" GLX_ARB_create_context GLX_ARB_create_context_profile GLX_EXT_framebuffer_sRGB",
+				" GLX_ARB_create_context GLX_ARB_create_context_profile",
+				1023 - strlen(glxextensions));
+		if(!strstr(glxextensions, "GLX_EXT_framebuffer_sRGB"))
+			strncat(glxextensions, " GLX_EXT_framebuffer_sRGB",
 				1023 - strlen(glxextensions));
 		return glxextensions;
 	}