InputStream: use int64_t instead of goffset

Decouple some more from GLib.

src/input/CdioParanoiaInputPlugin.cxx

@@ -250,7 +250,7 @@ input_cdio_open(const char *uri,
 
 static bool
 input_cdio_seek(struct input_stream *is,
-		goffset offset, int whence, Error &error)
+		InputPlugin::offset_type offset, int whence, Error &error)
 {
 	CdioParanoiaInputStream *cis = (CdioParanoiaInputStream *)is;
 

src/input/CurlInputPlugin.cxx

@@ -780,7 +780,7 @@ input_curl_read(struct input_stream *is, void *ptr, size_t size,
 	if (c->icy.IsDefined())
 		copy_icy_tag(c);
 
-	is->offset += (goffset)nbytes;
+	is->offset += (InputPlugin::offset_type)nbytes;
 
 	if (c->paused && curl_total_buffer_size(c) < CURL_RESUME_AT) {
 		c->base.mutex.unlock();
@@ -977,7 +977,8 @@ input_curl_easy_init(struct input_curl *c, Error &error)
 }
 
 static bool
-input_curl_seek(struct input_stream *is, goffset offset, int whence,
+input_curl_seek(struct input_stream *is, InputPlugin::offset_type offset,
+		int whence,
 		Error &error)
 {
 	struct input_curl *c = (struct input_curl *)is;
@@ -1022,7 +1023,7 @@ input_curl_seek(struct input_stream *is, goffset offset, int whence,
 	while (offset > is->offset && !c->buffers.empty()) {
 		auto &buffer = c->buffers.front();
 		size_t length = buffer.Available();
-		if (offset - is->offset < (goffset)length)
+		if (offset - is->offset < (InputPlugin::offset_type)length)
 			length = offset - is->offset;
 
 		const bool empty = !buffer.Consume(length);

src/input/FfmpegInputPlugin.cxx

@@ -34,6 +34,8 @@ extern "C" {
 #include <libavformat/avformat.h>
 }
 
+#include <glib.h>
+
 struct FfmpegInputStream {
 	struct input_stream base;
 
@@ -146,7 +148,8 @@ input_ffmpeg_eof(struct input_stream *is)
 }
 
 static bool
-input_ffmpeg_seek(struct input_stream *is, goffset offset, int whence,
+input_ffmpeg_seek(struct input_stream *is, InputPlugin::offset_type offset,
+		  int whence,
 		  Error &error)
 {
 	FfmpegInputStream *i = (FfmpegInputStream *)is;

src/input/FileInputPlugin.cxx

@@ -97,12 +97,13 @@ input_file_open(const char *filename,
 }
 
 static bool
-input_file_seek(struct input_stream *is, goffset offset, int whence,
+input_file_seek(struct input_stream *is, InputPlugin::offset_type offset,
+		int whence,
 		Error &error)
 {
 	FileInputStream *fis = (FileInputStream *)is;
 
-	offset = (goffset)lseek(fis->fd, (off_t)offset, whence);
+	offset = (InputPlugin::offset_type)lseek(fis->fd, (off_t)offset, whence);
 	if (offset < 0) {
 		error.SetErrno("Failed to seek");
 		return false;

src/input/RewindInputPlugin.cxx

@@ -164,7 +164,7 @@ input_rewind_read(struct input_stream *is, void *ptr, size_t size,
 
 		size_t nbytes = r->input->Read(ptr, size, error);
 
-		if (r->input->offset > (goffset)sizeof(r->buffer))
+		if (r->input->offset > (InputPlugin::offset_type)sizeof(r->buffer))
 			/* disable buffering */
 			r->tail = 0;
 		else if (r->tail == (size_t)is->offset) {
@@ -191,14 +191,16 @@ input_rewind_eof(struct input_stream *is)
 }
 
 static bool
-input_rewind_seek(struct input_stream *is, goffset offset, int whence,
+input_rewind_seek(struct input_stream *is, InputPlugin::offset_type offset,
+		  int whence,
 		  Error &error)
 {
 	RewindInputStream *r = (RewindInputStream *)is;
 
 	assert(is->ready);
 
-	if (whence == SEEK_SET && r->tail > 0 && offset <= (goffset)r->tail) {
+	if (whence == SEEK_SET && r->tail > 0 &&
+	    offset <= (InputPlugin::offset_type)r->tail) {
 		/* buffered seek */
 
 		assert(!r->ReadingFromBuffer() ||