feat: support libc for small devices

targets/esp32.memory.elf.ld

@@ -0,0 +1,26 @@
+/*
+ * IROM/DRAM definition in QEMU:
+ *     [ESP32_MEMREGION_IROM] = { 0x40000000, 0x70000 },
+ *     [ESP32_MEMREGION_DRAM] = { 0x3ffae000, 0x52000 },
+ *
+ * In theory we could use whole DRAM section, but I had some faults when using
+ * memory in range 0x3ffae000 - 0x3ffb0000
+ *
+ * But used memory range for data such as esp-idf for ESP32 to satisfy user's
+ * expectation on chip emulation
+ *
+ * Pass '--defsym=entire_dram_seg=1' to linker script to use whole DRAM
+ *
+ */
+
+MEMORY
+{
+  iram_seg  (X) : org = 0x40078000, len = 0x28000
+/* 64k at the end of DRAM, after ROM bootloader stack
+ * or entire DRAM (for QEMU only)
+ */
+  dram_seg (RW) : org = 0x3FFF0000 ,
+                  len = 0x10000
+}
+
+INCLUDE "targets/esp32.app.elf.ld";