bug in unix, missing brace

openglcanvas.cpp

@@ -29,8 +29,8 @@
   #define OPEN_FILE open
   #define LSEEK_FD lseek
   #define FOPEN_RO(_descriptor,_filename) \
-    (_descriptor=fopen(_filename,"r")); \
-    if((_descriptor)==NULL) \
+    _descriptor=fopen(_filename,"r"); \
+    if((_descriptor)==NULL){ \
         fprintf(stderr,"unable to open file '%s'\n",_filename); \
         exit(-1); \
     }