diff -ur dvipng-1.15.orig/special.c dvipng-1.15/special.c --- dvipng-1.15.orig/special.c 2015-03-02 20:33:55.000000000 +0100 +++ dvipng-1.15/special.c 2015-03-03 12:51:18.000000000 +0100 @@ -44,9 +44,9 @@ struct pscode { struct pscode* next; char* special; /* complete special */ - char* code; /* PS string, null if a file */ + const char* code; /* PS string, null if a file */ char* filename; /* file name, null if a string */ - char* postcode; /* post PS string */ + const char* postcode; /* post PS string */ struct filemmap fmmap; /* file mmap */ };