libxslt in Fedora mingw packages depends on it.

Writer's default is 0, but Word's default is 26 (15 in 1/8 pt)

Otherwise code using the lcms2 we build won't get the stdcall
decorations and linking will fail.

Nah, will use the patch by Lubos instead.

This reverts commit 85f07455.

The idea is to use libo_MINGW_CHECK_DLL for libs that must be available
(typically that would be the "main" library, e.g., libxml2 or libcurl)
and libo_MINGW_TRY_DLL for possible dependencies (that may not be the
same on different systems). All further references to the dlls are
exclusively through the configured variables or defines set from these
variables (e.g., instead of hardcoding libxml2-2.dll, use
$(MINGW_LIBXML2_DLL)).

The macros are documented in m4/mingw.m4 .

Files that must be changed when adding a new dll:
* configure.in
* config_host.mk.in
* external/mingw-dlls/makefile.mk
* scp2/source/ooo/makefile.mk
* scp2/source/ooo/mingw_dlls.scp

Use GG era abbreviation in one format instead of full GGG.

Hopefully this will allow pasting to external applications with whole
column/row selected while not affecting calc itself.

These two tests are not well designed and need 5 and 10 minute just to
check that we really return every row. This is not a good trade-off
between test coverage and execution time.

Enable them again with a better concept.