Add files via upload

[pmjherman]

These changes were made in order to make compilation of netcdf with opendap capabilities possible under MINGW-MSYS2. I refer to the email conversation with ticket netCDF #JZZ-916731. The present pull request is changed from my earlier patches, based on your response. In particular, I have avoided use of the generic compilation flag WIN32 but made everything as specific and tailored to the functions involved as possible. This should not interfere with other builds than builds under MINGW (I hope).

The changes, per file, are as follows:

1. /libdispatch/dutil.c Correction of a typing error in the code. I bumped onto this, probably because something else in the compilation had gone wrong, so I am not sure that this correction is absolutely needed. However, it will also not harm to correct
2. CMakeLists.txt The changes in this file are as follows: (a) in a number of places changes for MSVC are also needed for MINGW. These changes were copied from an existing MSYS2 compilation recipe, but instead of using the flag WIN32 I made it more specific (MINGW) so as not to interfere with other compilation procedures (e.g. Cygwin or others). (b) In addition, I defined two new variables that are set both under MSVC and MINGW. HAVE_WIN_TEMP expresses the fact that one has to look for the tmp directory using the Windows environmental variable TEMP, and is used in /libdispatch/ddispatch.c; HAVE_WIN_SSCANF expresses the fact that the Windows runtime library is used for the sscanf function (this is done both by MSVC and by MINGW). In the Windows implementation of sscanf, two differences occur: the specifier %hhu is not recognized, and NaN is not recognized as a special character sequence but results in an error if one assigns to a float or double. The flag HAVE_WIN_SSCANF is used in the files /lbdap2/dapcvt.c and /ncgen/cvt.c
3. config.h.cmake.in is changed in order to set the compiler flags HAVE_WIN_TEMP and HAVE_WIN_SSCANF with #cmakedefine commands
4. ncconfigure.h is changed in order to solve a problem with strlcat. This function is not available under MINGW, and the alternative formulation that belongs to the netcdf source could not be linked to certain functions because strlcat was not exported to the dll. I have changed the header in such a way that this export happens, but only when HAVE_STRLCAT is undefined. It should change nothing to builds where the function is natively present.

Note one point where interference with other builds is, in principle, possible. Some changes in the use of sscanf under MSVC were made specific to a certain version of MSVC in the file dapcvt.c, while I have now set the flag HAVE_WIN_SSCANF generic for all versions of MSVC. I did this because I could not find back any documentation from Microsoft suggesting that sscanf had been changed and the lacking functionality added in later versions. In addition, I think it very unlikely that lack of functionality was only present in a single version, not in earlier or later ones. However, I am not entirely certain about this and it is a matter of consideration

Note, further, that I only made changes to the CMake system, not to the config/autoconfig system as I did not use that and do not know very well how it functions.

[CLAassistant]

All committers have signed the CLA.

[WardF]

Having just finished a blocking task on our end, we are reviewing and catching up on pull requests. We will take care of the conflicts, etc, and review this, thank you!

[pmjherman]

Dear Ward, Thank you. I am not sure I did this properly. I started from version 4.6.0, but could not find a way in Github to branch from that version. Therefore I only uploaded the files that I had modified compared to 4.6.0, but it seemed to produce a mess on Github. I hope you can find out what it was meant to represent. If not, I can try to do it in a more proper way if you could give me a hint on how to do it. Peter Peter Herman T +31(0)88335 7862 E peter.herman@deltares.nl [Logo]<http://www.deltares.com/> www.deltares.com<http://www.deltares.com/> Postbus 177 2600 MH Delft [Deltares Twitter] <http://www.twitter.com/deltares> [Deltares LinkedIn]<http://www.linkedin.com/company/217430> [Deltares Facebook]<https://www.facebook.com/pages/Deltares/154189334634001> [Think before printing]Please consider the environment before printing this email From: Ward Fisher [mailto:notifications@github.com] Sent: donderdag 12 april 2018 23:00 To: Unidata/netcdf-c Cc: Peter Herman; Author Subject: Re: [Unidata/netcdf-c] Add files via upload (#905) Having just finished a blocking task on our end, we are reviewing and catching up on pull requests. We will take care of the conflicts, etc, and review this, thank you! - You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#905 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/AgC7e5Hoq1kuIWUzIQWBb2HllxikErIBks5tn8BigaJpZM4SuuVG>. DISCLAIMER: This message is intended exclusively for the addressee(s) and may contain confidential and privileged information. If you are not the intended recipient please notify the sender immediately and destroy this message. Unauthorized use, disclosure or copying of this message is strictly prohibited. The foundation 'Stichting Deltares', which has its seat at Delft, The Netherlands, Commercial Registration Number 41146461, is not liable in any way whatsoever for consequences and/or damages resulting from the improper, incomplete and untimely dispatch, receipt and/or content of this e-mail.

[DennisHeimbigner]

1. I am in the process of rebuilding dapcvt.c, so those changes here may get overwritten.
2. I do not understand the strlcat note; we provide a strlcat implementation when
   strlcat is not available; are you saying you use it or not?

[pmjherman]

Dennis, with respect to strlcat.
When the function is natively available, my changes do nothing.
When the function is not natively available, the netcdf implementation of it is used. However, for the linker to be able to find this function in a Windows system, it needs to be exported explicitly into the dll. That has to be done in the header file. My changes only do this: pick the implementation of strlcat provided by netcdf (if it is not natively available) and make sure its code arrives in the dll so that it can be linked to throughout the netcdf compilation process.
Hope it is clearer now.
Peter

[WardF]

Hi, can you re-push without Windows line endings? It makes comparing the changes in CMakeLists.txt difficult :)