Add -lpthread for libicu static

Author: auxten

sqlite3_opt_icu.go

@@ -8,7 +8,7 @@
 package sqlite3
 
 /*
-#cgo LDFLAGS: -licui18n -licuuc -licudata -lm -lstdc++
+#cgo LDFLAGS: -licui18n -licuuc -licudata -lm -lpthread -lstdc++
 #cgo CFLAGS: -DSQLITE_ENABLE_ICU -DU_STATIC_IMPLEMENTATION
 #cgo darwin CFLAGS: -I/usr/local/opt/icu4c/include
 #cgo darwin LDFLAGS: -L/usr/local/opt/icu4c/lib