Fix bug in LLVM bytecode runtime

Fixes a bug in the PtrVerifier pass when using LLVM >= v3.5 for the
bytecode signature runtime.

LLVM 3.5 changed the meaning of "use" and introduced "user". This fix
swaps out "use" keywords for "user" so the code functions correctly when
using LLVM 3.5+.

libclamav/c++/ClamBCRTChecks.cpp

@@ -778,8 +778,13 @@ namespace llvm {
 
       bool checkCond(Instruction *ICI, Instruction *I, bool equal)
       {
+#if LLVM_VERSION < 35
           for (Value::use_iterator JU=ICI->use_begin(),JUE=ICI->use_end();
                JU != JUE; ++JU) {
+#else
+          for (Value::user_iterator JU=ICI->user_begin(),JUE=ICI->user_end();
+               JU != JUE; ++JU) {
+#endif
               Value *JU_V = *JU;
               if (BranchInst *BI = dyn_cast<BranchInst>(JU_V)) {
                   if (!BI->isConditional())
@@ -802,8 +807,13 @@ namespace llvm {
 
       bool checkCondition(Instruction *CI, Instruction *I)
       {
+#if LLVM_VERSION < 35
           for (Value::use_iterator U=CI->use_begin(),UE=CI->use_end();
                U != UE; ++U) {
+#else
+          for (Value::user_iterator U=CI->user_begin(),UE=CI->user_end();
+               U != UE; ++U) {
+#endif
               Value *U_V = *U;
               if (ICmpInst *ICI = dyn_cast<ICmpInst>(U_V)) {
                   if (ICI->getOperand(0)->stripPointerCasts() == CI &&