Avoid redefinition of strcasecmp under mingw-w64

[mjwoods]

Fixes #2083

NetCDF defines strcasecmp as a preprocessor macro on Windows platforms. This is probably needed for the Microsoft compilers, but the header files used by mingw-w64 compilers define strcasecmp as an inline function.

If both the inline function and the macro definitions are used with gcc at high optimisation levels (specifically the flag -foptimize-sibling-calls, which is included by default at -O2 or higher), the OpenDAP tests hang.

On mingw-w64, the macro __MINGW32__ is defined in both 32-bit and 64-bit environments. If this macro is defined, the macro definition of strcasecmp can be disabled, which avoids the hang when running OpenDAP tests.

[DennisHeimbigner]

This should be changed in netcdf-c/include/ncconfigure.h
which already has a number of such tests, including one for strcasecmp.

[mjwoods]

Hi @DennisHeimbigner , I have attempted to implement the definitions of strcasecmp (and related functions) in ncconfigure.h, removing similar definitions from other files. Is that what you had in mind?

[DennisHeimbigner]

Hah! did not realize is was so ubiquitous.
Yes, centralizing into ncconfigure.h is what I meant.
There are, however some exceptions for code that is intended
to be "standalone" and independent of the netcdf library for a
a variety of reasons. These include the following:

1. libdispatch/nclists.c
2. libdispatch/ncjson.c
3. libdispatch/ncuri.c

So those probably should have your fix; in all other cases, adding config.h (if not already
there) is the right thing to do.

[mjwoods]

I have removed config.h from nclists.c and ncjson.c , restoring my earlier fix for mingw.

I have not changed ncuri.c at all yet, but it does include config.h .