From 92b3dfb42ca28dc2b837f4e33e685d7b98419cf2 Mon Sep 17 00:00:00 2001
From: David Given <dg@cowlark.com>
Date: Sun, 17 Jul 2022 00:47:49 +0200
Subject: [PATCH] Apparently Windows doesn't have strndup or index.

---
 mach/proto/mcg/main.c        |  2 +-
 mach/proto/mcg/mcg.h         |  1 +
 modules/src/system/strndup.c | 19 +++++++++++++++++++
 modules/src/system/system.h  |  5 +++++
 4 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 modules/src/system/strndup.c

diff --git a/mach/proto/mcg/main.c b/mach/proto/mcg/main.c
index aa0fa4816..9f4982d66 100644
--- a/mach/proto/mcg/main.c
+++ b/mach/proto/mcg/main.c
@@ -15,7 +15,7 @@ bool tracing(char k)
     if (!tracechars)
         return false;
 
-    return index(tracechars, k);
+    return strchr(tracechars, k);
 }
 
 void tracef(char k, const char* fmt, ...)
diff --git a/mach/proto/mcg/mcg.h b/mach/proto/mcg/mcg.h
index 0bd9928df..9991d5001 100644
--- a/mach/proto/mcg/mcg.h
+++ b/mach/proto/mcg/mcg.h
@@ -9,6 +9,7 @@
 #include <string.h>
 #include <assert.h>
 #include <errno.h>
+#include "system.h"
 #include "em_arith.h"
 #include "em_label.h"
 #include "em.h"
diff --git a/modules/src/system/strndup.c b/modules/src/system/strndup.c
new file mode 100644
index 000000000..798b9b71b
--- /dev/null
+++ b/modules/src/system/strndup.c
@@ -0,0 +1,19 @@
+#include <stdlib.h>
+#include <string.h>
+#include "system.h"
+
+#if defined WIN32
+/* Really? */
+char* strndup(const char* s, size_t n)
+{
+    size_t len = strnlen(s, n);
+    char* ns = malloc(len + 1);
+    if (!ns)
+        return NULL;
+
+    ns[len] = '\0';
+    memcpy(ns, s, len);
+    return ns;
+}
+#endif
+
diff --git a/modules/src/system/system.h b/modules/src/system/system.h
index 12c27916b..2489c1f03 100644
--- a/modules/src/system/system.h
+++ b/modules/src/system/system.h
@@ -84,4 +84,9 @@ void sys_basename(const char *str, register char *dst);
  * the same semantics as ISO C90 tmpnam() */
 char* sys_tmpnam(char *buffer);
 
+#if defined WIN32
+/* Really? */
+extern char* strndup(const char* s, size_t n);
+#endif
+
 #endif /* __SYSTEM_INCLUDED__ */