Introduce vc_setInterfaceFlags function
This patch adds a vc_setInterfaceFlags function to the C interface
with one possible flag, EXPRDELETE, which is set by default. The flag
controls whether the C interface deletes types and integer constant
expressions at vc_Destroy time. It is intended that clients which
perform their own memory management of these objects will be able to
clear this flag.
git-svn-id: https://stp-fast-prover.svn.sourceforge.net/svnroot/stp-fast-prover/trunk/stp@940
e59a4935-1847-0410-ae03-
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