Use micros() instead of cycle counting.

DHT.cpp

@@ -235,25 +235,30 @@ boolean DHT::read(bool force) {
 // in the very latest IDE versions):
 //   https://github.com./arduino/Arduino/blob/master/hardware/arduino/avr/cores/arduino/wiring_pulse.c
 uint32_t DHT::expectPulse(bool level) {
-  uint32_t count = 0;
-  // On AVR platforms use direct GPIO port access as it's much faster and better
-  // for catching pulses that are 10's of microseconds in length:
   #ifdef __AVR
+    uint32_t count = 0;
+    // On AVR platforms use direct GPIO port access as it's much faster and better
+    // for catching pulses that are 10's of microseconds in length:
     uint8_t portState = level ? _bit : 0;
     while ((*portInputRegister(_port) & _bit) == portState) {
       if (count++ >= _maxcycles) {
         return 0; // Exceeded timeout, fail.
       }
     }
-  // Otherwise fall back to using digitalRead (this seems to be necessary on ESP8266
-  // right now, perhaps bugs in direct port access functions?).
+    return count;
   #else
+    // Otherwise fall back to using digitalRead (this seems to be necessary on ESP8266
+    // right now, perhaps bugs in direct port access functions?).
+    unsigned long start = micros();
+    unsigned long end = start;
     while (digitalRead(_pin) == level) {
-      if (count++ >= _maxcycles) {
+      end = micros();
+      // When micros() wraps, we return failure. That should happen
+      // infrequently enough that it's not a big deal.
+      if (end - start >= _maxcycles || start > end) {
         return 0; // Exceeded timeout, fail.
       }
     }
+    return end - start;
   #endif
-
-  return count;
 }

DHT.h

@@ -64,6 +64,8 @@ class DHT {
 class InterruptLock {
   public:
    InterruptLock() {
+    // This is a nop on my esp32 Arduino system. noInterrupts() is defined to
+    // cli(), which is empty.
     noInterrupts();
    }
    ~InterruptLock() {