Handle missing function declarations and undefined/divergence of function names in windows.

 - Makefile: allow implicit functions warnings, define stricmp as macro for strcasecmp, define WIN32.
 - cc.h: check if BYTE_ORDER is not already defined (which is in windows toolchain)
 - socket.h: Check if timeval.h hasn't already been included before defining the timeval struct
 - Define __locale_c_type_ptr function, locale/ctype support is not enabled in windows toolchain.

Author: caiohamamura

Makefile

@@ -100,7 +100,7 @@ ifeq ($(OS),Windows_NT)
   else
     # It is gcc, may be cygwin
     # Can we use -fdata-sections?
-    CCFLAGS += -ffunction-sections -fno-jump-tables -fdata-sections -fpack-struct=4
+    CCFLAGS += -ffunction-sections -fno-jump-tables -fdata-sections -fpack-struct=4 -Wno-error=implicit-function-declaration -Dstricmp=strcasecmp -DWIN32
     AR = xtensa-lx106-elf-ar
     CC = xtensa-lx106-elf-gcc
     CXX = xtensa-lx106-elf-g++

app/include/arch/cc.h

@@ -42,11 +42,13 @@
 
 //#define LWIP_PROVIDE_ERRNO
 
+#ifndef BYTE_ORDER
 #if (1)
 #define BYTE_ORDER LITTLE_ENDIAN
 #else
 #define BYTE_ORDER BIG_ENDIAN
 #endif
+#endif
 
 
 typedef uint8_t    u8_t;

app/include/sys/socket.h

@@ -242,10 +242,13 @@ typedef uint32 socklen_t;
 #define O_NDELAY    1 /* same as O_NONBLOCK, for compatibility */
 #endif
 
+#ifndef _SYS__TIMEVAL_H_
 struct timeval {
 	long tv_sec; /* seconds */
 	long tv_usec; /* and microseconds */
 };
+#endif
+
 /* Flags for struct netconn.flags (u8_t) */
 /** TCP: when data passed to netconn_write doesn't fit into the send buffer,
  this temporarily stores whether to wake up the original application task

app/libc/stdlib.c

@@ -10,6 +10,15 @@
 #define TRUE  1
 #define FALSE 0
 #endif
+
+#ifdef WIN32
+// locale/ctype support not enabled for windows
+__attribute__((weak))
+const char* __locale_ctype_ptr(void) {
+    return NULL; 
+}
+#endif
+
 double powersOf10[] ICACHE_STORE_ATTR ICACHE_RODATA_ATTR =   /* Table giving binary powers of 10.  Entry */
 {
     10.,            /* is 10^2^i.  Used to convert decimal */