package/ibm-sw-tpm2: fix glibc build errors

package/ibm-sw-tpm2: fix glibc build errors

In order to not have to define all architecture bitness variants in
src/LibSupport.h to conditionally define RADIX_BITS, a patch was created
to depend on LONG_BIT being defined via limits.h

For glibc, LONG_BIT is behind a _XOPEN_SOURCE define guard so patch the
makefile to define this macro as well as _DEFAULT_SOURCE.

Defining _XOPEN_SOURCE requires _DEFAULT_SOURCE to be explicitly defined
for builds to succeed as it is no longer impliclty defined when
_XOPEN_SOURCE is defined.

Fixes:
	http://autobuild.buildroot.net/results/bc145dd23c80a0660300766d0c114a00ed2e52b6/
	http://autobuild.buildroot.net/results/1d84e70c30d4d0719274aa4f3edc01772beb24a3/

Fixes: 19bd089004 ("package/ibm-sw-tpm2: fix patch to address musl builds")
Signed-off-by: Vincent Fazio <vfazio@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>