[PATCH v2 4/8] Test for number of mkdir() arguments

Windows' mkdir() takes only 1 argument, so add a test for that.
---
 CHANGES:
 v2: dropped MSVC change as unrelated

 configure.ac     |  1 +
 include/compat.h | 15 ++++++++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index a5648fe5..b2892d27 100644
--- a/configure.ac
+++ b/configure.ac
@@ -898,6 +898,7 @@ AC_PROG_GCC_TRADITIONAL
 AC_FUNC_MEMCMP
 AC_TYPE_SIGNAL
 AC_FUNC_STRFTIME
+AC_FUNC_MKDIR
 AC_CHECK_FUNCS(mktime timegm gettimeofday select poll wcrtomb)
 AC_CHECK_FUNCS(strchr strdup strndup strstr strtol strtok strsep)
 AC_CHECK_FUNCS(asprintf vasprintf snprintf vsnprintf getpass setenv)
diff --git a/include/compat.h b/include/compat.h
index acb91fc6..cae13a69 100644
--- a/include/compat.h
+++ b/include/compat.h
@@ -207,6 +207,20 @@ int vasprintf(char **ptr, const char *format, va_list ap);
 time_t timegm(struct tm *tm);
 #endif
 
+#if HAVE_MKDIR
+# if MKDIR_TAKES_ONE_ARG
+   /* Mingw32 */
+#  define mkdir(a,b) mkdir(a)
+# endif
+#else
+# if HAVE__MKDIR
+   /* plain Win32 */
+#  define mkdir(a,b) _mkdir(a)
+# else
+#  error "Don't know how to create a directory on this system."
+# endif
+#endif
+
 /*
  * The following code was taken from W. Richard Stevens'
  * "UNIX Network Programming", Volume 1, Second Edition.
-- 
2.20.0.rc2