Index: uspace/lib/posix/include/posix/stdio.h
===================================================================
--- uspace/lib/posix/include/posix/stdio.h	(revision 95174bfdc3425cbd2a229f8813c1b4c459e4a264)
+++ uspace/lib/posix/include/posix/stdio.h	(revision af5037d7d69a9a68ea2c7d4cda870c058f02d4d9)
@@ -61,5 +61,5 @@
     FILE *__restrict__ stream);
 
-#ifdef _LARGEFILE64_SOURCE
+#if defined(_LARGEFILE64_SOURCE) || defined(_GNU_SOURCE)
 extern int fseeko64(FILE *stream, off64_t offset, int whence);
 extern off64_t ftello64(FILE *stream);
Index: uspace/lib/posix/include/posix/sys/types.h
===================================================================
--- uspace/lib/posix/include/posix/sys/types.h	(revision 95174bfdc3425cbd2a229f8813c1b4c459e4a264)
+++ uspace/lib/posix/include/posix/sys/types.h	(revision af5037d7d69a9a68ea2c7d4cda870c058f02d4d9)
@@ -55,5 +55,5 @@
 #endif
 
-#ifdef _LARGEFILE64_SOURCE
+#if defined(_LARGEFILE64_SOURCE) || defined(_GNU_SOURCE)
 typedef int64_t off64_t;
 #endif
Index: uspace/lib/posix/include/posix/unistd.h
===================================================================
--- uspace/lib/posix/include/posix/unistd.h	(revision 95174bfdc3425cbd2a229f8813c1b4c459e4a264)
+++ uspace/lib/posix/include/posix/unistd.h	(revision af5037d7d69a9a68ea2c7d4cda870c058f02d4d9)
@@ -86,5 +86,5 @@
 extern int dup2(int fildes, int fildes2);
 
-#ifdef _LARGEFILE64_SOURCE
+#if defined(_LARGEFILE64_SOURCE) || defined(_GNU_SOURCE)
 extern off64_t lseek64(int fildes, off64_t offset, int whence);
 extern int ftruncate64(int fildes, off64_t length);