Add FindWrapSystemMd4c.cmake so that the old md4c target can be used
as well as the new one and set WrapSystemMd4c_FOUND.
Link to the imported target WrapSystemMd4c::WrapSystemMd4c if the
system library is used.
Add qt_find_package line to find the package in configure.cmake.
Fix the condition for enabling system-textmarkdownreader, it includes
testing for textmarkdownreader because even if the code would compile
correctly without it, it looks strange when the output says
"textmarkdownreader no" and under "using system libmd4c yes" even if
libmd4c is not used.
Use system include when system-markdownreader is enabled.
Add library mapping for libmd4c.
Change-Id: Id5d5b13d6691a8c1cdf627238887977c847c1e67
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
