[cpp] Support `VarTemplate` and `VarTemplateSpecialization` about esbmc

[fbrausse]

With #1739 merged, which adds VarTemplate and VarTemplatePartialSpecialization, only this is needed, I believe:

diff --git a/src/clang-c-frontend/clang_c_convert.cpp b/src/clang-c-frontend/clang_c_convert.cpp
index 8b275ac727..0291c20860 100644
--- a/src/clang-c-frontend/clang_c_convert.cpp
+++ b/src/clang-c-frontend/clang_c_convert.cpp
@@ -116,6 +116,7 @@ bool clang_c_convertert::get_decl(const clang::Decl &decl, exprt &new_expr)
 
   // Declaration of variables
   case clang::Decl::Var:
+  case clang::Decl::VarTemplateSpecialization:
   {
     const clang::VarDecl &vd = static_cast<const clang::VarDecl &>(decl);
     return get_var(vd, new_expr);

and some test cases, probably.

[lucasccordeiro]

A PR to fix this issue would be welcome here ;-)

[intrigus-lgtm]

@lucasccordeiro from me?

[fbrausse]

@intrigus-lgtm or from me ;)

[lucasccordeiro]

@intrigus-lgtm: can I ask you whether you could submit a PR that fixes this issue? :-)

[intrigus-lgtm]

Can try this weekend.
After that I can then submit some new bugs^^

[lucasccordeiro]

Great. Many thanks, @intrigus-lgtm.