*: check defined(_WIN32) instead of defined(WIN32)

Only _WIN32 is defined by the compiler, and WIN32 is not standardized
and may be missing.

Closes #169

src/util/FormatString.cxx

@@ -23,14 +23,14 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#ifdef WIN32
+#ifdef _WIN32
 #include <string.h>
 #endif
 
 AllocatedString<>
 FormatStringV(const char *fmt, va_list args)
 {
-#ifndef WIN32
+#ifndef _WIN32
 	va_list tmp;
 	va_copy(tmp, args);
 	const int length = vsnprintf(NULL, 0, fmt, tmp);

src/util/HugeAllocator.cxx

@@ -96,7 +96,7 @@ HugeDiscard(void *p, size_t size) noexcept
 #endif
 }
 
-#elif defined(WIN32)
+#elif defined(_WIN32)
 
 void *
 HugeAllocate(size_t size)

src/util/HugeAllocator.hxx

@@ -65,7 +65,7 @@ HugeFree(void *p, size_t size) noexcept;
 void
 HugeDiscard(void *p, size_t size) noexcept;
 
-#elif defined(WIN32)
+#elif defined(_WIN32)
 #include <windows.h>
 
 gcc_malloc

src/util/StringAPI.hxx

@@ -105,7 +105,7 @@ gcc_nonnull_all
 static inline char *
 UnsafeCopyStringP(char *dest, const char *src) noexcept
 {
-#if defined(WIN32) || defined(__BIONIC__)
+#if defined(_WIN32) || defined(__BIONIC__)
   /* emulate stpcpy() */
   UnsafeCopyString(dest, src);
   return dest + StringLength(dest);

src/util/TimeParser.cxx

@@ -35,7 +35,7 @@
 #include <assert.h>
 #include <time.h>
 
-#if !defined(__GLIBC__) && !defined(WIN32)
+#if !defined(__GLIBC__) && !defined(_WIN32)
 
 /**
  * Determine the time zone offset in a portable way.
@@ -59,7 +59,7 @@ ParseTimePoint(const char *s, const char *format)
 	assert(s != nullptr);
 	assert(format != nullptr);
 
-#ifdef WIN32
+#ifdef _WIN32
 	/* TODO: emulate strptime()? */
 	(void)s;
 	(void)format;
@@ -80,5 +80,5 @@ ParseTimePoint(const char *s, const char *format)
 
 	return std::chrono::system_clock::from_time_t(t);
 
-#endif /* !WIN32 */
+#endif /* !_WIN32 */
 }

src/util/WStringAPI.hxx

@@ -101,7 +101,7 @@ gcc_nonnull_all
 static inline wchar_t *
 UnsafeCopyStringP(wchar_t *dest, const wchar_t *src) noexcept
 {
-#if defined(WIN32) || defined(__BIONIC__) || defined(__OpenBSD__) || \
+#if defined(_WIN32) || defined(__BIONIC__) || defined(__OpenBSD__) || \
 	defined(__NetBSD__)
   /* emulate wcpcpy() */
   UnsafeCopyString(dest, src);