Remove obsolete CLANG_VERSION checks

...now that the (Linux) Clang baseline has been bumped ot 5.0.2 (see
<https://lists.freedesktop.org/archives/libreoffice/2018-November/081435.html>
"minutes of ESC call ...").

(This commit precedes a commit that will actually enforce Clang >= 5.0.2 in
configure.ac.  However, it was easier to do it in this order, as that other
commit will drop CLANG_VERSION when building with Apple Clang (where version
numbers are different from upstream), so these checks would start to fail
there.)

Change-Id: Icb3df0d0cf476e14c5453f02bdfc9e5bed066ca1
Reviewed-on: https://gerrit.libreoffice.org/63898
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

include/unoidl/unoidl.hxx

@@ -15,7 +15,6 @@
 #include <cassert>
 #include <vector>
 
-#include <config_clang.h>
 #include <osl/mutex.hxx>
 #include <rtl/ref.hxx>
 #include <rtl/ustring.hxx>
@@ -506,9 +505,6 @@ public:
         };
 
         Constructor():
-#if defined __clang__ && CLANG_VERSION == 30800
-            annotations(),
-#endif
             defaultConstructor(true) {}
 
         Constructor(

svx/source/customshapes/EnhancedCustomShapeFunctionParser.cxx

@@ -19,7 +19,6 @@
 
 #include <sal/config.h>
 
-#include <config_clang.h>
 #include <svx/EnhancedCustomShape2d.hxx>
 #include <rtl/ustring.hxx>
 #include <sal/log.hxx>
@@ -466,7 +465,7 @@ public:
         mpSecondArg( rSecondArg )
     {
     }
-#if (defined(__clang__) && CLANG_VERSION >=30700) || (defined (__GNUC__) && __GNUC__ >= 8)
+#if defined(__clang__) || (defined (__GNUC__) && __GNUC__ >= 8)
     //GetEquationValueAsDouble calls isFinite on the result
     __attribute__((no_sanitize("float-divide-by-zero")))
 #endif