Reduce static RAM usage (#2140)

esphome/core/log.h

@@ -7,6 +7,7 @@
 #include "WString.h"
 #endif
 
+#include "esphome/core/macros.h"
 // avoid esp-idf redefining our macros
 #include "esphome/core/esphal.h"
 
@@ -162,4 +163,28 @@ int esp_idf_log_vprintf_(const char *format, va_list args);  // NOLINT
 #define ONOFF(b) ((b) ? "ON" : "OFF")
 #define TRUEFALSE(b) ((b) ? "TRUE" : "FALSE")
 
+#ifdef USE_STORE_LOG_STR_IN_FLASH
+#define LOG_STR(s) PSTR(s)
+
+// From Arduino 2.5 onwards, we can pass a PSTR() to printf(). For previous versions, emulate support
+// by copying the message to a local buffer first. String length is limited to 63 characters.
+// https://github.com/esp8266/Arduino/commit/6280e98b0360f85fdac2b8f10707fffb4f6e6e31
+#include <core_version.h>
+#if defined(ARDUINO_ARCH_ESP8266) && ARDUINO_VERSION_CODE < VERSION_CODE(2, 5, 0)
+#define LOG_STR_ARG(s) \
+  ({ \
+    char __buf[64]; \
+    __buf[63] = '\0'; \
+    strncpy_P(__buf, s, 63); \
+    __buf; \
+  })
+#else
+#define LOG_STR_ARG(s) (s)
+#endif
+
+#else
+#define LOG_STR(s) (s)
+#define LOG_STR_ARG(s) (s)
+#endif
+
 }  // namespace esphome