Build everything as C++ (#1176)

include/platform.hpp

@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: MIT */
+
+// platform-specific hacks
+
+#ifndef RGBDS_PLATFORM_H
+#define RGBDS_PLATFORM_H
+
+// MSVC doesn't have str(n)casecmp, use a suitable replacement
+#ifdef _MSC_VER
+# include <string.h>
+# define strcasecmp _stricmp
+# define strncasecmp _strnicmp
+#else
+# include <strings.h>
+#endif
+
+// MSVC has deprecated strdup in favor of _strdup
+#ifdef _MSC_VER
+# define strdup _strdup
+#endif
+
+// MSVC prefixes the names of S_* macros with underscores,
+// and doesn't define any S_IS* macros; define them ourselves
+#ifdef _MSC_VER
+# define S_IFMT _S_IFMT
+# define S_IFDIR _S_IFDIR
+# define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
+#endif
+
+// gcc has __PRETTY_FUNCTION__, MSVC has __FUNCSIG__, __func__ is standard
+#ifndef __PRETTY_FUNCTION__
+# ifdef __FUNCSIG__
+#  define __PRETTY_FUNCTION__ __FUNCSIG__
+# else
+#  define __PRETTY_FUNCTION__ __func__
+# endif
+#endif
+
+// MSVC doesn't use POSIX types or defines for `read`
+#ifdef _MSC_VER
+# include <io.h>
+# define STDIN_FILENO 0
+# define STDOUT_FILENO 1
+# define STDERR_FILENO 2
+# define ssize_t int
+# define SSIZE_MAX INT_MAX
+#else
+# include <fcntl.h>
+# include <unistd.h>
+#endif
+
+// C++ doesn't support `[static N]` for array arguments from C99 or C11
+#define MIN_NB_ELMS(N) // static (N)
+#define ARR_QUALS(...) // __VA_ARGS__
+#define NONNULL(ptr) *ptr // ptr[static 1]
+#define restrict
+
+// C++ doesn't support designated array initializers, but they're a gcc extension
+#ifdef __GNUC__
+# define AT(index) [index] =
+#else
+# define AT(index)
+#endif
+
+// MSVC uses a different name for O_RDWR, and needs an additional _O_BINARY flag
+#ifdef _MSC_VER
+# include <fcntl.h>
+# define O_RDWR _O_RDWR
+# define S_ISREG(field) ((field) & _S_IFREG)
+# define O_BINARY _O_BINARY
+# define O_TEXT _O_TEXT
+#elif !defined(O_BINARY) // Cross-compilers define O_BINARY
+# define O_BINARY 0 // POSIX says we shouldn't care!
+# define O_TEXT 0 // Assume that it's not defined either
+#endif // _MSC_VER
+
+// Windows has stdin and stdout open as text by default, which we may not want
+#if defined(_MSC_VER) || defined(__MINGW32__)
+# include <io.h>
+# define setmode(fd, mode) _setmode(fd, mode)
+#else
+# define setmode(fd, mode) (0)
+#endif
+
+#endif // RGBDS_PLATFORM_H