diff --git a/libvips/iofuncs/init.c b/libvips/iofuncs/init.c
index fe39f9a0..815c64c5 100644
--- a/libvips/iofuncs/init.c
+++ b/libvips/iofuncs/init.c
@@ -1161,7 +1161,7 @@ vips_guess_prefix( const char *argv0, const char *env_name )
 
 	/* Already set?
 	 */
-        if( (prefix = g_getenv( env_name )) 
+        if( (prefix = g_getenv( env_name )) )
                 return( prefix );
 
 #ifdef G_OS_WIN32