Generate and scan documentation output in Ddoc tests.
The tests in gdc.test/compilable/ddoc*.d don't require the module to be
compiled all the way down to object code. Instead, only compile the
test sources with -fdoc, and scan the generated html content.
gcc/testsuite/ChangeLog:
PR d/88039
* gdc.test/gdc-test.exp (gdc-convert-args): Handle -D.
(dmd2dg): Check generated html in ddoc tests.
(gdc-do-test): Set dg-do-what-default to compile for ddoc tests.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@266933 138bc75d-0d04-0410-961f-82ee72b054a4