Make git_remote_supported_url() public and shorten error string

include/git2/remote.h

@@ -197,6 +197,14 @@ GIT_EXTERN(int) git_remote_update_tips(git_remote *remote);
  */
 GIT_EXTERN(int) git_remote_valid_url(const char *url);
 
+/**
+ * Return whether the passed URL is supported by this version of the library.
+ *
+ * @param url the url to check
+ * @return 1 if the url is supported, 0 otherwise
+*/
+GIT_EXTERN(int) git_remote_supported_url(const char* url);
+
 /**
  * Get a list of the configured remotes for a repo
  *

src/transport.c

@@ -10,7 +10,6 @@
 #include "git2/net.h"
 #include "transport.h"
 #include "path.h"
-#include <regex.h>
 
 static struct {
 	char *prefix;
@@ -67,7 +66,7 @@ int git_transport_new(git_transport **out, const char *url)
 	fn = transport_find_fn(url);
 
 	if (fn == NULL)
-		return git__throw(GIT_EINVALIDARGS, "No supported transport mechanism found for URL or path. Either libgit2 has not implemented this transport protocol, or it can not find the specified path.");
+		return git__throw(GIT_EINVALIDARGS, "Unsupported URL or non-existent path");
 
 	error = fn(&transport);
 	if (error < GIT_SUCCESS)

src/transport.h

@@ -109,13 +109,6 @@ int git_transport_dummy(struct git_transport **transport);
 */
 int git_transport_valid_url(const char *url);
 
-/**
-  Returns true if the passed URL is supported by this version of libgit2.
-  (or, more technically, the transport method inferred by libgit is supported
-  by this version of libgit2).
-*/
-int git_remote_supported_url(const char* url);
-
 typedef struct git_transport git_transport;
 typedef int (*git_transport_cb)(git_transport **transport);