sokol_gfx.h: add a gl_max_vertex_uniform_vectors item to sg_limits

sokol_gfx.h

@@ -871,7 +871,8 @@ typedef struct sg_limits {
     int max_image_size_3d;          // max width/height/depth of SG_IMAGETYPE_3D images
     int max_image_size_array;       // max width/height of SG_IMAGETYPE_ARRAY images
     int max_image_array_layers;     // max number of layers in SG_IMAGETYPE_ARRAY images
-    int max_vertex_attrs;           // <= SG_MAX_VERTEX_ATTRIBUTES (only on some GLES2 impls)
+    int max_vertex_attrs;           // <= SG_MAX_VERTEX_ATTRIBUTES or less (on some GLES2 impls)
+    int gl_max_vertex_uniform_vectors;  // <= GL_MAX_VERTEX_UNIFORM_VECTORS (only on GL backends)
 } sg_limits;
 
 /*
@@ -5517,6 +5518,9 @@ _SOKOL_PRIVATE void _sg_gl_init_limits(void) {
         gl_int = SG_MAX_VERTEX_ATTRIBUTES;
     }
     _sg.limits.max_vertex_attrs = gl_int;
+    glGetIntegerv(GL_MAX_VERTEX_UNIFORM_VECTORS, &gl_int);
+    _SG_GL_CHECK_ERROR();
+    _sg.limits.gl_max_vertex_uniform_vectors = gl_int;
     #if !defined(SOKOL_GLES2)
     if (!_sg.gl.gles2) {
         glGetIntegerv(GL_MAX_3D_TEXTURE_SIZE, &gl_int);

util/sokol_gfx_imgui.h

@@ -3732,6 +3732,7 @@ _SOKOL_PRIVATE void _sg_imgui_draw_caps_panel(void) {
     igText("    max_image_size_array: %d", l.max_image_size_array);
     igText("    max_image_array_layers: %d", l.max_image_array_layers);
     igText("    max_vertex_attrs: %d", l.max_vertex_attrs);
+    igText("    gl_max_vertex_uniform_vectors: %d", l.gl_max_vertex_uniform_vectors);
     igText("\nUsable Pixelformats:");
     for (int i = (int)(SG_PIXELFORMAT_NONE+1); i < (int)_SG_PIXELFORMAT_NUM; i++) {
         sg_pixel_format fmt = (sg_pixel_format)i;