Add C89 stdint compatibility

sj_stdint.h

@@ -0,0 +1,66 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Small fixed-width integer compatibility layer for SJ3.
+ *
+ * In C99 or newer translation units, use <stdint.h>. In C89 translation
+ * units, provide the fixed-width names that SJ3 needs when the host integer
+ * model has matching types.
+ */
+
+#ifndef SJ_STDINT_H_
+#define SJ_STDINT_H_
+
+#if defined(HAVE_C99_STDINT) && HAVE_C99_STDINT && \
+    defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
+#include <stdint.h>
+#else
+
+#include <limits.h>
+
+#if !defined(UINT8_MAX)
+# if UCHAR_MAX == 255
+typedef signed char int8_t;
+typedef unsigned char uint8_t;
+#  define UINT8_MAX UCHAR_MAX
+# else
+#  error "SJ3 requires an 8-bit unsigned char"
+# endif
+#endif
+
+#if !defined(UINT16_MAX)
+# if USHRT_MAX == 65535
+typedef short int16_t;
+typedef unsigned short uint16_t;
+#  define UINT16_MAX USHRT_MAX
+# else
+#  error "SJ3 requires a 16-bit unsigned short"
+# endif
+#endif
+
+#if !defined(UINT32_MAX)
+# if UINT_MAX == 4294967295U
+typedef int int32_t;
+typedef unsigned int uint32_t;
+#  define UINT32_MAX UINT_MAX
+# elif ULONG_MAX == 4294967295UL
+typedef long int32_t;
+typedef unsigned long uint32_t;
+#  define UINT32_MAX ULONG_MAX
+# else
+#  error "SJ3 requires a 32-bit integer type"
+# endif
+#endif
+
+#if !defined(UINT64_MAX) && (ULONG_MAX > 4294967295UL)
+typedef long int64_t;
+typedef unsigned long uint64_t;
+# define UINT64_MAX ULONG_MAX
+#elif !defined(UINT64_MAX) && (defined(_MSC_VER) || defined(_WIN32))
+typedef __int64 int64_t;
+typedef unsigned __int64 uint64_t;
+#endif
+
+#endif
+
+#endif /* SJ_STDINT_H_ */