Fix for pthreads on MSYS2 & MINGW

[lealem47]

Description

Fix for pthread issues in #6874 and #6838.

Includes a fix for a truncated output warning. This was resolved by incrementing MAX_PATH and MAX_FILENAME_SZ to 260+1 as the max value on windows is 260 (https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation?tabs=registry)

In file included from wolfcrypt/src/wc_port.c:28:
wolfcrypt/src/wc_port.c: In function 'wc_ReadDirFirst':
./wolfssl/wolfcrypt/types.h:674:35: error: 'strncpy' output may be truncated copying between 0 and 255 bytes from a string of length 259 [-Werror=stringop-truncation]
  674 |         #define XSTRNCPY(s1,s2,n) strncpy((s1),(s2),(n))
      |                                   ^~~~~~~~~~~~~~~~~~~~~~
wolfcrypt/src/wc_port.c:635:13: note: in expansion of macro 'XSTRNCPY'
  635 |             XSTRNCPY(ctx->name + pathLen + 1,
      |             ^~~~~~~~
wolfcrypt/src/wc_port.c: In function 'wc_ReadDirNext':
./wolfssl/wolfcrypt/types.h:674:35: error: 'strncpy' output may be truncated copying between 0 and 255 bytes from a string of length 259 [-Werror=stringop-truncation]
  674 |         #define XSTRNCPY(s1,s2,n) strncpy((s1),(s2),(n))
      |                                   ^~~~~~~~~~~~~~~~~~~~~~
wolfcrypt/src/wc_port.c:788:13: note: in expansion of macro 'XSTRNCPY'
  788 |             XSTRNCPY(ctx->name + pathLen + 1,
      |             ^~~~~~~~
cc1: all warnings being treated as errors
make[2]: *** [Makefile:6351: wolfcrypt/src/src_libwolfssl_la-wc_port.lo] Error 1

Testing

Reproduced reports on mingw. These changes resolved the problems locally.

Checklist

• added tests
• updated/added doxygen
• updated appropriate READMEs
• Updated manual and documentation

[JacobBarthelmeh]

Passes now with ./autogen.sh && ./configure --host=x86_64-w64-mingw32 && make. Thanks