Make source seek/tell functions public.
diff --git a/lib/zip.h b/lib/zip.h
index aa9b683..67ef791 100644
--- a/lib/zip.h
+++ b/lib/zip.h
@@ -391,8 +391,12 @@
 ZIP_EXTERN int zip_source_open(zip_source_t *);
 ZIP_EXTERN zip_int64_t zip_source_read(zip_source_t *, void *, zip_uint64_t);
 ZIP_EXTERN void zip_source_rollback_write(zip_source_t *);
+ZIP_EXTERN int zip_source_seek(zip_source_t *, zip_int64_t, int);
 ZIP_EXTERN zip_int64_t zip_source_seek_compute_offset(zip_uint64_t, zip_uint64_t, void *, zip_uint64_t, zip_error_t *);
+ZIP_EXTERN int zip_source_seek_write(zip_source_t *, zip_int64_t, int);
 ZIP_EXTERN int zip_source_stat(zip_source_t *, zip_stat_t *);
+ZIP_EXTERN zip_int64_t zip_source_tell(zip_source_t *);
+ZIP_EXTERN zip_int64_t zip_source_tell_write(zip_source_t *);
 ZIP_EXTERN zip_int64_t zip_source_write(zip_source_t *, const void *, zip_uint64_t);
 ZIP_EXTERN zip_source_t *zip_source_zip(zip_t *, zip_t *, zip_uint64_t, zip_flags_t, zip_uint64_t, zip_int64_t);
 ZIP_EXTERN int zip_stat(zip_t *, const char *, zip_flags_t, zip_stat_t *);
diff --git a/lib/zip_source_seek.c b/lib/zip_source_seek.c
index 6779ad7..c3f4703 100644
--- a/lib/zip_source_seek.c
+++ b/lib/zip_source_seek.c
@@ -35,7 +35,7 @@
 #include "zipint.h"
 
 
-int
+ZIP_EXTERN int
 zip_source_seek(zip_source_t *src, zip_int64_t offset, int whence)
 {
     zip_source_args_seek_t args;
diff --git a/lib/zip_source_seek_write.c b/lib/zip_source_seek_write.c
index cd4c938..6660766 100644
--- a/lib/zip_source_seek_write.c
+++ b/lib/zip_source_seek_write.c
@@ -35,7 +35,7 @@
 #include "zipint.h"
 
 
-int
+ZIP_EXTERN int
 zip_source_seek_write(zip_source_t *src, zip_int64_t offset, int whence)
 {
     zip_source_args_seek_t args;
diff --git a/lib/zip_source_tell.c b/lib/zip_source_tell.c
index cbbfdfa..f1c10b5 100644
--- a/lib/zip_source_tell.c
+++ b/lib/zip_source_tell.c
@@ -35,7 +35,7 @@
 #include "zipint.h"
 
 
-zip_int64_t
+ZIP_EXTERN zip_int64_t
 zip_source_tell(zip_source_t *src)
 {
     if (src->source_closed) {
diff --git a/lib/zip_source_tell_write.c b/lib/zip_source_tell_write.c
index 18c0855..2fa1507 100644
--- a/lib/zip_source_tell_write.c
+++ b/lib/zip_source_tell_write.c
@@ -35,7 +35,7 @@
 #include "zipint.h"
 
 
-zip_int64_t
+ZIP_EXTERN zip_int64_t
 zip_source_tell_write(zip_source_t *src)
 {
     if (!ZIP_SOURCE_IS_OPEN_WRITING(src)) {
diff --git a/lib/zipint.h b/lib/zipint.h
index 29bd28e..28ea354 100644
--- a/lib/zipint.h
+++ b/lib/zipint.h
@@ -209,11 +209,7 @@
 zip_source_t *zip_source_layered_create(zip_source_t *src, zip_source_layered_callback cb, void *ud, zip_error_t *error);
 zip_source_t *zip_source_pkware(zip_t *, zip_source_t *, zip_uint16_t, int, const char *);
 int zip_source_remove(zip_source_t *);
-int zip_source_seek(zip_source_t *, zip_int64_t, int);
-int zip_source_seek_write(zip_source_t *, zip_int64_t, int);
 zip_int64_t zip_source_supports(zip_source_t *src);
-zip_int64_t zip_source_tell(zip_source_t *);
-zip_int64_t zip_source_tell_write(zip_source_t *);
 zip_source_t *zip_source_window(zip_t *, zip_source_t *, zip_uint64_t, zip_uint64_t);