Changes to Autoconf/Automake configuration files for windows port. Added AX_CHECK_WINDOWS macro to specify TARGET_WINDOWS when windows.h exists. Special handling for krb5: hard-code include and lib paths relative to the --with-krb5 directory. Add -Zi compile flag and -debug link flags on windows; remove -Werror -Wall -Wunused-paramater; I should find and add msvc equivalents use -DCONFIG_WIN32_DEFAULTS -DUSE_INTERNAL_CRYPTO instead of myriad -DEAP_FOO.
Consolidate thread-local data. Also add windows versions of MUTEX macros. Together, these changes eliminate dependency on pthread for windows and centralize the platform-specific code to deal with thread-local storage.
Fixed calling convention for functions exported from gssapi.h On Windows all functions exported from gssapi.h have KRB5_CALLCONV calling convention. This is needed in order to compile correctly on Windows.