The C89 standard and later defines the <string.h> header as part of the
standard headers [1]. Functions memcmp, memmove, strerror, strchr, strstr,
and others are all part of C89 and <string.h> header definition.
Some build systems used to define the presence of these functions via
HAVE_MEMCMP, HAVE_MEMMOVE, HAVE_STRERROR, HAVE_STRCHR, HAVE_STRSTR
symbols. These aren't used in oniguruma library anymore and can be
ommitted from the config files for windows systems.
[1]: https://port70.net/~nsz/c/c89/c89-draft.html#4.11
#define GETGROUPS_T int\r
#define HAVE_ALLOCA 1\r
#define HAVE_DUP2 1\r
-#define HAVE_MEMCMP 1\r
-#define HAVE_MEMMOVE 1\r
#define HAVE_MKDIR 1\r
#define HAVE_STRCASECMP 1\r
#define HAVE_STRNCASECMP 1\r
-#define HAVE_STRERROR 1\r
#define HAVE_STRFTIME 1\r
-#define HAVE_STRCHR 1\r
-#define HAVE_STRSTR 1\r
#define HAVE_STRTOD 1\r
#define HAVE_STRTOL 1\r
#define HAVE_STRTOUL 1\r
#define GETGROUPS_T int\r
#define HAVE_ALLOCA 1\r
#define HAVE_DUP2 1\r
-#define HAVE_MEMCMP 1\r
-#define HAVE_MEMMOVE 1\r
#define HAVE_MKDIR 1\r
#define HAVE_STRCASECMP 1\r
#define HAVE_STRNCASECMP 1\r
-#define HAVE_STRERROR 1\r
#define HAVE_STRFTIME 1\r
-#define HAVE_STRCHR 1\r
-#define HAVE_STRSTR 1\r
#define HAVE_STRTOD 1\r
#define HAVE_STRTOL 1\r
#define HAVE_STRTOUL 1\r
#define GETGROUPS_T int\r
#define HAVE_ALLOCA 1\r
#define HAVE_DUP2 1\r
-#define HAVE_MEMCMP 1\r
-#define HAVE_MEMMOVE 1\r
#define HAVE_MKDIR 1\r
#define HAVE_STRCASECMP 1\r
#define HAVE_STRNCASECMP 1\r
-#define HAVE_STRERROR 1\r
#define HAVE_STRFTIME 1\r
-#define HAVE_STRCHR 1\r
-#define HAVE_STRSTR 1\r
#define HAVE_STRTOD 1\r
#define HAVE_STRTOL 1\r
#define HAVE_STRTOUL 1\r