sqlite icu load collation in Wt

I am trying to use sqlite(3) icu_load_collation on Wt. (Wt 3.3.3 on ubuntu). I have added

#define SQLITE_ENABLE_LOAD_EXTENSION 1
#define SQLITE_ENABLE_COLUMN_METADATA 1
#define SQLITE_ENABLE_ICU 1

lines to sqlite3.h (srd/Wt/Dbo/backed/amalgamation/sqlite3.h) file and run make and sudo make install on build. It supposed to work, but it did not. Compiler gives an error saying there is no function as "icu_load_collation" where I implemented. In summary, I am trying to use "icu_load_collation" on Wt, but failed so far. Any help would be appreciated.