diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 526105d..9e8c039 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -32,7 +32,7 @@ if(WIN32)
         win32/w32util.cpp)
 else()
     set(util_SOURCES
-        fltk/fltkutil.cpp)
+        unix/unixutil.cpp)
 endif()
 
 # libslvs
diff --git a/src/fltk/fltkutil.cpp b/src/unix/unixutil.cpp
similarity index 91%
rename from src/fltk/fltkutil.cpp
rename to src/unix/unixutil.cpp
index 700029b..7326f30 100644
--- a/src/fltk/fltkutil.cpp
+++ b/src/unix/unixutil.cpp
@@ -1,5 +1,5 @@
 //-----------------------------------------------------------------------------
-// Utility functions used by the FLTK port. Notably, our memory allocation;
+// Utility functions used by the Unix port. Notably, our memory allocation;
 // we use two separate allocators, one for long-lived stuff and one for
 // stuff that gets freed after every regeneration of the model, to save us
 // the trouble of freeing the latter explicitly.
@@ -13,8 +13,6 @@
 #include <string.h>
 #include <stdio.h>
 
-#include <FL/filename.H>
-
 #include "solvespace.h"
 
 void dbp(const char *str, ...)
@@ -31,9 +29,9 @@ void dbp(const char *str, ...)
 
 void GetAbsoluteFilename(char *file)
 {
-    char absoluteFile[PATH_MAX];
-    fl_filename_absolute(absoluteFile, sizeof(absoluteFile), file);
-    strcpy(file, absoluteFile);
+    char expanded[MAX_PATH];
+    realpath(file, expanded);
+    strcpy(file, expanded);
 }
 
 //-----------------------------------------------------------------------------