From 4a0cdca28c60d223fa7a5fb71453da7596d27288 Mon Sep 17 00:00:00 2001
From: Sebastian Andersson <sebastian@bittr.nu>
Date: Thu, 14 Dec 2017 07:38:09 +0100
Subject: [PATCH] Export pgmspace symbols to C (#3955)

---
 cores/esp8266/pgmspace.cpp |  4 ++++
 cores/esp8266/pgmspace.h   | 12 +++++++-----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/cores/esp8266/pgmspace.cpp b/cores/esp8266/pgmspace.cpp
index e705a32f6..f3c376dca 100644
--- a/cores/esp8266/pgmspace.cpp
+++ b/cores/esp8266/pgmspace.cpp
@@ -24,6 +24,8 @@
 #include <stdarg.h>
 #include "pgmspace.h"
 
+extern "C" {
+
 size_t strnlen_P(PGM_P s, size_t size) {
     const char* cp;
     for (cp = s; size != 0 && pgm_read_byte(cp) != '\0'; cp++, size--);
@@ -286,3 +288,5 @@ int vsnprintf_P(char* str, size_t strSize, PGM_P formatP, va_list ap) {
 
     return ret;
 }
+
+} // extern "C"
diff --git a/cores/esp8266/pgmspace.h b/cores/esp8266/pgmspace.h
index a785e2639..2e3a71f3a 100644
--- a/cores/esp8266/pgmspace.h
+++ b/cores/esp8266/pgmspace.h
@@ -4,16 +4,14 @@
 #include <stdint.h>
 #include <stdio.h>
 
-#ifdef __ets__
-
 #ifdef __cplusplus
 extern "C" {
 #endif
+
+#ifdef __ets__
+
 #include "ets_sys.h"
 #include "osapi.h"
-#ifdef __cplusplus
-}
-#endif
 
 #define PROGMEM     ICACHE_RODATA_ATTR
 #define PGM_P  		const char *
@@ -136,4 +134,8 @@ static inline uint16_t pgm_read_word_inlined(const void* addr) {
 #define pgm_read_float_far(addr) 	pgm_read_float(addr)
 #define pgm_read_ptr_far(addr)		pgm_read_ptr(addr)
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif //__PGMSPACE_H_