[latex][bugfix][win32][cmake] ignore CMAKE_FIND_ROOT_PATH for latexmkrc.cmake

When cross compiling for windows it is necessary to tweak CMAKE_FIND_ROOT_PATH_MODE_* to modify default behavior of FIND_XXX() commands to search for headers/libs in the target environment and search for programs in the build host environment.

This lead to a problem when searching for latexmkrc.cmake.

We now explicitly change the UseLatexMk find_file call to ignore the CMAKE_FIND_ROOT_PATH and thus beeing able to find the file in the source directory.

@gruenich can we backport this to 2.7?

added backport label

merged

mentioned in commit 3263b577

mentioned in commit 0bd38ef1

mentioned in merge request !742 (merged)

Cherry-picking to 2.7 is on its way.

Do you mind creating a similar merge request upstream to https://github.com/dokempf/UseLatexMk?

mentioned in commit a577e22d