lib: Fix definition of strcasecmp() for PCI_OS_WINDOWS

lib: Fix definition of strcasecmp() for PCI_OS_WINDOWS

UCRT, MSVCRT and CRTDLL runtime libraries provides only _strcmpi()
function and not strcmpi().

MinGW32 has static libraries libcoldname.a and libmoldname.a which provides
strcmpi() function (as link-time redirect to _strcmpi()). libcoldname.a is
automatically linked when compiling for CRTDLL runtime and libmoldname.a
for MSVCRT runtime.

MinGW-w64 has only libmoldname.a library with strcmpi() function and it is
linked to final executable only when compiling for MSVCRT runtime.
when linking with MSVCRT.

To prevent dependency on particular linking configuration and MinGW
toolchain, use set strcasecmp() as alias to _strcmpi() function which is
provided by any runtime library.