Remove $prefix/include from the default -I path because it can cause the build to...

Remove $prefix/include from the default -I path because it can cause the build to pick up an unintended copy of sqlite3.h. Extend the ICU configure support (the origin of -I$prefix/include) to enable fetching the -I path from icu-config and apply it only to those objects which need it.

FossilOrigin-Name: f778dfdd6d6a4975c903d8ca0ebfb4fa917d543289136ea0ab740cb47d2510c1