compat: some mkdir() do not like a slash at the end

Introduce a compatibility helper for platforms with such a mkdir().

Signed-off-by: Joachim Schmitz <jojo@schmitz-digital.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

compat/mkdir.c

@@ -0,0 +1,24 @@
+#include "../git-compat-util.h"
+#undef mkdir
+
+/* for platforms that can't deal with a trailing '/' */
+int compat_mkdir_wo_trailing_slash(const char *dir, mode_t mode)
+{
+	int retval;
+	char *tmp_dir = NULL;
+	size_t len = strlen(dir);
+
+	if (len && dir[len-1] == '/') {
+		if ((tmp_dir = strdup(dir)) == NULL)
+			return -1;
+		tmp_dir[len-1] = '\0';
+	}
+	else
+		tmp_dir = (char *)dir;
+
+	retval = mkdir(tmp_dir, mode);
+	if (tmp_dir != dir)
+		free(tmp_dir);
+
+	return retval;
+}

git-compat-util.h

@@ -162,6 +162,11 @@
 #define probe_utf8_pathname_composition(a,b)
 #endif
 
+#ifdef MKDIR_WO_TRAILING_SLASH
+#define mkdir(a,b) compat_mkdir_wo_trailing_slash((a),(b))
+extern int compat_mkdir_wo_trailing_slash(const char*, mode_t);
+#endif
+
 #ifndef NO_LIBGEN_H
 #include <libgen.h>
 #else