jack2: fix build issue with glibc

With glibc 2.16, we get following build error when building jack2:

  [193/247] cxx: tests/iodelay.cpp -> build/tests/iodelay.cpp.4.o
  ../tests/iodelay.cpp:171:43: error: 'UINT32_MAX' was not declared in this scope
  ../tests/iodelay.cpp:171:55: error: 'UINT32_MAX' was not declared in this scope
  ../tests/iodelay.cpp:172:44: error: 'UINT32_MAX' was not declared in this scope
  ../tests/iodelay.cpp:172:56: error: 'UINT32_MAX' was not declared in this scope

In glibc 2.17 or older version, Header <stdint.h> defines these macros
for C++ only if explicitly requested by defining __STDC_LIMIT_MACROS.

We can't use <cstdint> since it requires C++11 standard.

Fixes:

  http://autobuild.buildroot.net/results/369ce208ffea43dad75ba0a13469159b341e3bf5/



Signed-off-by: Rahul Bedarkar <rahul.bedarkar@imgtec.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>