Building in release mode fails with gcc version 4.3.3

[Catherine Hope]

Building in release mode (the default for building Harmony  Select) will
currently fail on gcc version 4.3.3 as warnings are treated as errors and
that compiler version is more strict in regards to things like not checking
return codes of library functions.  The files affected are:

     [exec] hyfiletext.c:234: warning: ignoring return value of ‘wctomb’,
declared with attribute warn_unused_result
     [exec] hyosdump.c:86: warning: ignoring return value of ‘chdir’,
declared with attribute warn_unused_result
     [exec] linux/../hysl.c:306: warning: ignoring return value of ‘mbtowc’,
declared with attribute warn_unused_result
     [exec] procimpl.c:176: warning: ignoring return value of ‘write’,
declared with attribute warn_unused_result
     [exec] procimpl.c:180: warning: ignoring return value of ‘write’,
declared with attribute warn_unused_result
     [exec] procimpl.c:195: warning: ignoring return value of ‘write’,
declared with attribute warn_unused_result
     [exec] procimpl.c:215: warning: ignoring return value of ‘read’,
declared with attribute warn_unused_result
     [exec] authnix.c:144: warning: ignoring return value of ‘getgroups’,
declared with attribute warn_unused_result
     [exec] ../shared/SurfaceDataStructure.h:177: warning: inline function
‘void updateCache(SURFACE_STRUCTURE*, JNIEnv*, _jobject*, bool, int, int,
int, int)’ used but never defined