Fix hspcmp for EMSCRIPTEN2

Author: onitama

src/hsp3/emscripten/supio_emscripten.h

@@ -11,6 +11,8 @@ size_t utf8strlen(const char *target);
 char *mem_ini( int size );
 void mem_bye( void *ptr );
 int mem_save( char *fname, void *mem, int msize, int seekofs );
+char *mem_alloc( void *base, int newsize, int oldsize );
+
 void strcase( char *str );
 int strcpy2( char *str1, char *str2 );
 int strcat2( char *str1, char *str2 );