Move .C to .CPP in the code (#5696)

Use g++ to compile core files to get additional C++ checks on the code.

Also move libb64 constants to PROGMEM, saving ~128 bytes of heap when used.

Author: earlephilhower

cores/esp8266/StackThunk.c renamed to cores/esp8266/StackThunk.cpp

@@ -27,6 +27,9 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include "StackThunk.h"
+#include <ets_sys.h>
+
+extern "C" {
 
 uint32_t *stack_thunk_ptr = NULL;
 uint32_t *stack_thunk_top = NULL;
@@ -115,8 +118,10 @@ void stack_thunk_dump_stack()
   }
   ets_printf(">>>stack>>>\n");
   while (pos < stack_thunk_ptr) {
-    ets_printf("%08x:  %08x %08x %08x %08x\n", pos, pos[0], pos[1], pos[2], pos[3]);
+    ets_printf("%08x:  %08x %08x %08x %08x\n", (int32_t)pos, pos[0], pos[1], pos[2], pos[3]);
     pos += 4;
   }
   ets_printf("<<<stack<<<\n");
 }
+
+};

cores/esp8266/cont_util.c renamed to cores/esp8266/cont_util.cpp

@@ -23,6 +23,7 @@
 #include <string.h>
 #include "ets_sys.h"
 
+extern "C" {
 
 #define CONT_STACKGUARD 0xfeefeffe
 
@@ -80,3 +81,5 @@ void cont_repaint_stack(cont_t *cont)
         cont->stack[pos] = CONT_STACKGUARD;
     }
 }
+
+};

cores/esp8266/core_esp8266_eboot_command.c renamed to cores/esp8266/core_esp8266_eboot_command.cpp

@@ -23,7 +23,9 @@
 #include <stdbool.h>
 #include "eboot_command.h"
 
-uint32_t crc_update(uint32_t crc, const uint8_t *data, size_t length)
+extern "C" {
+
+static uint32_t crc_update(uint32_t crc, const uint8_t *data, size_t length)
 {
     uint32_t i;
     bool bit;
@@ -45,7 +47,7 @@ uint32_t crc_update(uint32_t crc, const uint8_t *data, size_t length)
     return crc;
 }
 
-uint32_t eboot_command_calculate_crc32(const struct eboot_command* cmd)
+static uint32_t eboot_command_calculate_crc32(const struct eboot_command* cmd)
 {
     return crc_update(0xffffffff, (const uint8_t*) cmd, 
                       offsetof(struct eboot_command, crc32));
@@ -86,3 +88,4 @@ void eboot_command_clear()
     RTC_MEM[offsetof(struct eboot_command, crc32) / sizeof(uint32_t)] = 0;
 }
 
+};

cores/esp8266/core_esp8266_flash_utils.c renamed to cores/esp8266/core_esp8266_flash_utils.cpp

@@ -25,6 +25,7 @@
 #include <stdbool.h>
 #include "flash_utils.h"
 
+extern "C" {
 
 int SPIEraseAreaEx(const uint32_t start, const uint32_t size)
 {
@@ -62,3 +63,4 @@ int SPIEraseAreaEx(const uint32_t start, const uint32_t size)
     return 0;
 }
 
+};

cores/esp8266/core_esp8266_i2s.c renamed to cores/esp8266/core_esp8266_i2s.cpp

@@ -23,11 +23,11 @@
 #include "Arduino.h"
 #include "osapi.h"
 #include "ets_sys.h"
-
-
 #include "i2s_reg.h"
 #include "i2s.h"
 
+extern "C" {
+
 #define SLC_BUF_CNT (8)  // Number of buffers in the I2S circular buffer
 #define SLC_BUF_LEN (64) // Length of one buffer, in 32-bit words.
 
@@ -573,3 +573,5 @@ void i2s_end() {
     rx = NULL;
   }
 }
+
+};

cores/esp8266/core_esp8266_noniso.c renamed to cores/esp8266/core_esp8266_noniso.cpp

@@ -29,6 +29,8 @@
 #include <math.h>
 #include "stdlib_noniso.h"
 
+extern "C" {
+
 char* ltoa(long value, char* result, int base) {
     return itoa((int)value, result, base);
 }
@@ -109,3 +111,5 @@ char * dtostrf(double number, signed char width, unsigned char prec, char *s) {
     *out = 0;
     return s;
 }
+
+};