treewide: remove use of C++ style comments

C++ style comment ("//") are not specified by the ISO C90 standard and
thus do not conform to it. While libgit2 aims to conform to C90, we did
not enforce it until now, which is why quite a lot of these
non-conforming comments have snuck into our codebase. Do a tree-wide
conversion of all C++ style comments to the supported C style comments
to allow us enforcing strict C90 compliance in a later commit.

Author: pks-t

examples/general.c

@@ -145,11 +145,13 @@ static void oid_parsing(git_oid *oid)
 	 */
 	git_oid_fromstr(oid, hex);
 
-	// Once we've converted the string into the oid value, we can get the raw
-	// value of the SHA by accessing `oid.id`
-
-	// Next we will convert the 20 byte raw SHA1 value to a human readable 40
-	// char hex value.
+	/*
+	 * Once we've converted the string into the oid value, we can get the raw
+	 * value of the SHA by accessing `oid.id`
+	 *
+	 * Next we will convert the 20 byte raw SHA1 value to a human readable 40
+	 * char hex value.
+	 */
 	printf("\n*Raw to Hex*\n");
 	out[GIT_OID_HEXSZ] = '\0';
 

examples/network/clone.c

@@ -48,7 +48,7 @@ static void print_progress(const progress_data *pd)
 
 static int sideband_progress(const char *str, int len, void *payload)
 {
-	(void)payload; // unused
+	(void)payload; /* unused */
 
 	printf("remote: %.*s", len, str);
 	fflush(stdout);
@@ -82,15 +82,15 @@ int do_clone(git_repository *repo, int argc, char **argv)
 	const char *path = argv[2];
 	int error;
 
-	(void)repo; // unused
+	(void)repo; /* unused */
 
-	// Validate args
+	/* Validate args */
 	if (argc < 3) {
 		printf ("USAGE: %s <url> <path>\n", argv[0]);
 		return -1;
 	}
 
-	// Set up options
+	/* Set up options */
 	checkout_opts.checkout_strategy = GIT_CHECKOUT_SAFE;
 	checkout_opts.progress_cb = checkout_progress;
 	checkout_opts.progress_payload = &pd;
@@ -100,7 +100,7 @@ int do_clone(git_repository *repo, int argc, char **argv)
 	clone_opts.fetch_opts.callbacks.credentials = cred_acquire_cb;
 	clone_opts.fetch_opts.callbacks.payload = &pd;
 
-	// Do the clone
+	/* Do the clone */
 	error = git_clone(&cloned_repo, url, path, &clone_opts);
 	printf("\n");
 	if (error != 0) {

examples/network/index-pack.c

@@ -19,8 +19,10 @@
 #endif
 #include "common.h"
 
-// This could be run in the main loop whilst the application waits for
-// the indexing to finish in a worker thread
+/*
+ * This could be run in the main loop whilst the application waits for
+ * the indexing to finish in a worker thread
+ */
 static int index_cb(const git_transfer_progress *stats, void *data)
 {
 	(void)data;

examples/network/ls-remote.c

@@ -12,7 +12,7 @@ static int use_remote(git_repository *repo, char *name)
 	size_t refs_len, i;
 	git_remote_callbacks callbacks = GIT_REMOTE_CALLBACKS_INIT;
 
-	// Find the remote by name
+	/* Find the remote by name */
 	error = git_remote_lookup(&remote, repo, name);
 	if (error < 0) {
 		error = git_remote_create_anonymous(&remote, repo, name);

src/notes.c

@@ -285,7 +285,7 @@ static int note_write(
 	git_oid oid;
 	git_tree *tree = NULL;
 
-	// TODO: should we apply filters?
+	/* TODO: should we apply filters? */
 	/* create note object */
 	if ((error = git_blob_create_frombuffer(&oid, repo, note, strlen(note))) < 0)
 		goto cleanup;

src/refspec.c

@@ -16,7 +16,7 @@
 
 int git_refspec__parse(git_refspec *refspec, const char *input, bool is_fetch)
 {
-	// Ported from https://github.com/git/git/blob/f06d47e7e0d9db709ee204ed13a8a7486149f494/remote.c#L518-636
+	/* Ported from https://github.com/git/git/blob/f06d47e7e0d9db709ee204ed13a8a7486149f494/remote.c#L518-636 */
 
 	size_t llen;
 	int is_glob = 0;

src/signature.c

@@ -247,7 +247,7 @@ int git_signature__parse(git_signature *sig, const char **buffer_out,
 
 			if ((tz_start[0] != '-' && tz_start[0] != '+') ||
 				git__strtol32(&offset, tz_start + 1, &tz_end, 10) < 0) {
-				//malformed timezone, just assume it's zero
+				/* malformed timezone, just assume it's zero */
 				offset = 0;
 			}
 

src/trailer.c

@@ -36,7 +36,7 @@ static const char *next_line(const char *str)
 	if (nl) {
 		return nl + 1;
 	} else {
-		// return pointer to the NUL terminator:
+		/* return pointer to the NUL terminator: */
 		return str + strlen(str);
 	}
 }
@@ -310,12 +310,12 @@ int git_message_trailers(git_message_trailer_array *trailer_arr, const char *mes
 				}
 
 				if (isalnum(*ptr) || *ptr == '-') {
-					// legal key character
+					/* legal key character */
 					NEXT(S_KEY);
 				}
 
 				if (*ptr == ' ' || *ptr == '\t') {
-					// optional whitespace before separator
+					/* optional whitespace before separator */
 					*ptr = 0;
 					NEXT(S_KEY_WS);
 				}
@@ -325,7 +325,7 @@ int git_message_trailers(git_message_trailer_array *trailer_arr, const char *mes
 					NEXT(S_SEP_WS);
 				}
 
-				// illegal character
+				/* illegal character */
 				GOTO(S_IGNORE);
 			}
 			case S_KEY_WS: {
@@ -341,7 +341,7 @@ int git_message_trailers(git_message_trailer_array *trailer_arr, const char *mes
 					NEXT(S_SEP_WS);
 				}
 
-				// illegal character
+				/* illegal character */
 				GOTO(S_IGNORE);
 			}
 			case S_SEP_WS: {
@@ -369,7 +369,7 @@ int git_message_trailers(git_message_trailer_array *trailer_arr, const char *mes
 			}
 			case S_VALUE_NL: {
 				if (*ptr == ' ') {
-					// continuation;
+					/* continuation; */
 					NEXT(S_VALUE);
 				}
 

src/transports/smart.c

@@ -82,15 +82,15 @@ static bool is_malformed_http_header(const char *http_header)
 	const char *c;
 	int name_len;
 
-	// Disallow \r and \n
+	/* Disallow \r and \n */
 	c = strchr(http_header, '\r');
 	if (c)
 		return true;
 	c = strchr(http_header, '\n');
 	if (c)
 		return true;
 
-	// Require a header name followed by :
+	/* Require a header name followed by : */
 	name_len = http_header_name_length(http_header);
 	if (name_len < 1)
 		return true;
@@ -112,7 +112,7 @@ static bool is_forbidden_custom_header(const char *custom_header)
 	unsigned long i;
 	int name_len = http_header_name_length(custom_header);
 
-	// Disallow headers that we set
+	/* Disallow headers that we set */
 	for (i = 0; i < ARRAY_SIZE(forbidden_custom_headers); i++)
 		if (strncmp(forbidden_custom_headers[i], custom_header, name_len) == 0)
 			return true;

src/win32/posix_w32.c

@@ -832,7 +832,7 @@ int p_mkstemp(char *tmp_path)
 		return -1;
 #endif
 
-	return p_open(tmp_path, O_RDWR | O_CREAT | O_EXCL, 0744); //-V536
+	return p_open(tmp_path, O_RDWR | O_CREAT | O_EXCL, 0744); /* -V536 */
 }
 
 int p_access(const char* path, mode_t mode)