Move the closure of the subset of flang/runtime/*.h header files that
are referenced by source files outside flang/runtime (apart from unit tests)
into a new directory (flang/include/flang/Runtime) so that relative
include paths into ../runtime need not be used.

flang/runtime/pgmath.h.inc is moved to flang/include/flang/Evaluate;
it's not used by the runtime.

Differential Revision: https://reviews.llvm.org/D109107

We should only need to spell the language out in .h files.

Differential Revision: https://reviews.llvm.org/D109138

Fix the external-io unittest under Windows.

In particular, fixes the following issues:

 1.  When creating a temporary file, open it with read+write permissions
     using the _O_RDWR flag. _S_IREAD and _S_IWRITE are for the file
     permissions of the created file.

 2. _chsize returns 0 on success (just like ftruncate).

 3. To set a std::optional, use its assign-operator overload instead of
    getting a reference to its value and overwrite that. The latter is
    invalid if the std::optional has no value, and is caught by
    msvc's debug STL.

The non-GTest unittest is currently not executed under Windows because
of the added .exe extension to the output file: external-io.text.exe.
llvm-lit skips the file because .exe is not in the lists of test
suffixes (.test is). D105315 is going to change that by converting it
to a GTest-test.

Reviewed By: awarzynski

Differential Revision: https://reviews.llvm.org/D106726

F18 was sigalling an end-of-file error condition when reading an
unformatted sequential input file without an ultimate newline
(or CR-LF). Other Fortran implementations can handle it, so change
the runtime to support it.

Differential Revision: https://reviews.llvm.org/D106321

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D94707

The flags F_OK, R_OK and W_OK are defined in unistd.h, which does not exist under the Windows platform. Windows still defines the `access` function. Its access flags are documented at https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/access-waccess. For compatibility, define the flags F_OK, R_OK and W_OK using these constants.

This patch is part of the series to make flang compilable with MS Visual Studio <http://lists.llvm.org/pipermail/flang-dev/2020-July/000448.html>.

Reviewed By: klausler

Differential Revision: https://reviews.llvm.org/D88508

Defining macros for min and max breaks using std::min and std::max. Defining NOMINMAX before including the header stops them from being defined.

See https://web.archive.org/web/20170911092732/https://support.microsoft.com/en-us/help/143208/prb-using-stl-in-windows-program-can-cause-min-max-conflicts for details.

This patch is part of the series to [[ http://lists.llvm.org/pipermail/flang-dev/2020-July/000448.html | make flang compilable with MS Visual Studio ]].

Reviewed By: isuruf

Differential Revision: https://reviews.llvm.org/D85656

Extend the raw file wrapper to get accessibility, positioning,
and size information.  This is needed for INQUIRE (to follow).

Differential Revision: https://reviews.llvm.org/D85160

Anonymous Fortran unit files (e.g., "./fort.7") need to be created
O_RDWR so that they can be written, rewound, and read.  Other
files opened with no ACTION= specifier need to set read/write
permissions based on the file, if it exists.

Reviewed By: sscalpone

Differential Revision: https://reviews.llvm.org/D84063

This was causing the build to fail on macos.

Differential Revision: https://reviews.llvm.org/D83237