Add a compatibility interface for ohash.

This include's espie@'s wholesale src/lib/libc/ohash directory from OpenBSD
into compat_ohash.c (with a single copyright/license notice at the top)
and src/include/ohash.h as compat_ohash.h.
The ohash_int.h part of compat_ohash.c has been changed only in that ohash.h
points to compat_ohash.h.
Added HAVE_OHASH test (test-ohash.c) to Makefile.
In mandocdb.c and mansearch.c, check HAVE_OHASH test for inclusion.

1 files changed, 19 insertions, 0 deletions

diff --git a/test-ohash.c b/test-ohash.c
new file mode 100644
index 00000000..72b3e3dd
--- /dev/null
+++ b/test-ohash.c
@@ -0,0 +1,19 @@
+#include <stdint.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <ohash.h>
+
+void *xalloc(size_t sz, void *arg) { return(calloc(sz,1)); }
+void xfree(void *p, size_t sz, void *arg) { free(p); }
+
+int
+main(void)
+{
+	struct ohash h;
+	struct ohash_info i;
+	i.halloc = i.alloc = xalloc;
+	i.free = free;
+	ohash_init(&h, 2, &i);
+	ohash_delete(&h);
+	return 0;
+}