add a descriptive comment to integer.h

include/integer.h

@@ -2,7 +2,32 @@
 /*      Copyright (c) 2016 by Michael Allison          */
 /* NetHack may be freely redistributed.  See license for details. */
 
-/* integer.h -- provide sized integer types */
+/* integer.h -- provide sized integer types
+ *
+ * We try to sort out a way to provide sized integer types
+ * in here. The strong preference is to try and let a
+ * compiler-supplied header file set up the types.
+ *
+ * If your compiler is C99 conforming and sets a value of
+ * __STDC_VERSION__ >= 199901L, then <stdint.h> is supposed
+ * to be available for inclusion.
+ *
+ * If your compiler doesn't set __STDC_VERSION__ to indicate
+ * full conformance to C99, but does actually supply a suitable
+ * <stdint.h>, you can pass a compiler flag -DHAS_STDINT_H
+ * during build to cause the inclusion of <stdint.h> anyway.
+ *
+ * If <stdint.h> doesn't get included, then the code in the
+ * STDINT_WORKAROUND section of code is not skipped and will
+ * be used to set up the types.
+ *
+ * We acknowledge that some ongoing maintenance may be needed
+ * over time if people send us code updates for making the
+ * determination of whether <stdint.h> is available, or
+ * require adjustments to the base type used for some
+ * compiler/platform combinations.
+ *
+ */
 
 #ifndef INTEGER_H
 #define INTEGER_H
@@ -24,6 +49,9 @@
 #endif
 
 #ifndef SKIP_STDINT_WORKAROUND /* !C99 */
+/*
+ * STDINT_WORKAROUND section begins here
+ */
 typedef unsigned char uint8_t;
 typedef short int16_t;
 typedef unsigned short uint16_t;