glx: Fix GLX_NV_float_buffer fbconfig handling

Since we didn't record this attribute from the server, we wouldn't
account for it in glXChooseFBConfig, and glXGetFBConfigAttrib wouldn't
know about it.

Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14221>

src/glx/glxcmds.c

@@ -1035,6 +1035,7 @@ fbconfigs_compatible(const struct glx_config * const a,
    MATCH_MASK(drawableType);
    MATCH_MASK(renderType);
    MATCH_DONT_CARE(sRGBCapable);
+   MATCH_DONT_CARE(floatComponentsNV);
 
    /* There is a bug in a few of the XFree86 DDX drivers.  They contain
     * visuals with a "transparent type" of 0 when they really mean GLX_NONE.

src/glx/glxconfig.c

@@ -186,10 +186,12 @@ glx_config_get(struct glx_config * mode, int attribute, int *value_return)
    case GLX_Y_INVERTED_EXT:
       *value_return = mode->yInverted;
       return 0;
-
    case GLX_FRAMEBUFFER_SRGB_CAPABLE_EXT:
       *value_return = mode->sRGBCapable;
       return 0;
+   case GLX_FLOAT_COMPONENTS_NV:
+      *value_return = mode->floatComponentsNV;
+      return 0;
 
       /* Applications are NOT allowed to query GLX_VISUAL_SELECT_GROUP_SGIX.
        * It is ONLY for communication between the GLX client and the GLX

src/glx/glxconfig.h

@@ -99,6 +99,9 @@ struct glx_config {
 
     /* EXT_framebuffer_sRGB */
     GLint sRGBCapable;
+
+    /* NV_float_buffer */
+    GLint floatComponentsNV;
 };
 
 extern GLint _gl_convert_from_x_visual_type(int visualType);

src/glx/glxext.c

@@ -612,6 +612,9 @@ __glXInitializeVisualConfigFromTags(struct glx_config * config, int count,
          if (fbconfig_style_tags)
             bp++;
          break;
+      case GLX_FLOAT_COMPONENTS_NV:
+         config->floatComponentsNV = *bp++;
+         break;
       case None:
          i = count;
          break;