Generate wrapper aliases only if requested and not by default

Defining the aliases by default results in conflicts when including
headers from multiple modules as e.g. SWIG_PendingException_get() is
defined in all of them, and could also easily result in other unwanted
clashes, so make this opt-in and update the examples and tests relying
on using the wrappers without the module prefix to define
SWIG_DEFINE_WRAPPER_ALIASES explicitly.

Examples/test-suite/c/cpp_basic_template_function_runme.c

@@ -1,4 +1,6 @@
 #include <assert.h>
+
+#define SWIG_DEFINE_WRAPPER_ALIASES
 #include "cpp_basic_template_function/cpp_basic_template_function_wrap.h"
 
 int main() {