Remove thread_local EPA data in favor of using mjData stack.

PiperOrigin-RevId: 900201369
Change-Id: I82fbe9bf0ef9ea117c2124353d876dd42a57fb3a

src/engine/engine_support.c

@@ -526,6 +526,7 @@ void mj_xfrcAccumulate(const mjModel* m, mjData* d, mjtNum* qfrc) {
 // returns the smallest distance between two geoms (using nativeccd)
 static mjtNum mj_geomDistanceCCD(const mjModel* m, mjData* d, int g1, int g2,
                                  mjtNum distmax, mjtNum fromto[6]) {
+  mj_markStack(d);
   mjCCDConfig config;
   mjCCDStatus status;
 
@@ -534,12 +535,14 @@ static mjtNum mj_geomDistanceCCD(const mjModel* m, mjData* d, int g1, int g2,
   config.tolerance = m->opt.ccd_tolerance;
   config.max_contacts = 1;        // want contacts
   config.dist_cutoff = distmax;   // want geom distances
+  config.buffer = mj_stackAllocByte(d, mjc_ccdSize(config.max_iterations), sizeof(mjtNum));
 
   mjCCDObj obj1, obj2;
   mjc_initCCDObj(&obj1, m, d, g1, 0);
   mjc_initCCDObj(&obj2, m, d, g2, 0);
 
   mjtNum dist = mjc_ccd(&config, &status, &obj1, &obj2);
+  mj_freeStack(d);
 
   // witness points are only computed if dist <= distmax
   if (fromto && status.nx > 0) {