let's have #include "umock_end_mocks.h" and #include "umock_begin_mocks.h"

Those 2 headers would contain

#define ENABLE_MOCKS

respectively
#undef ENABLE_MOCKS
#include "umock_c/umock_c_prod.h"

and should have a mechanism where
1. "umock_begin_mocks.h" after "umock_begin_mocks.h" is error
2. "umock_end_mocks.h" without "umock_begin_mocks.h" is error
3. "umock_end_mocks.h" after "umock_end_mocks.h" is error

Start by reading the existing ENABLE_MOCKS handling and umock_c/umock_c_prod.h, then inspect how the proposed umock_begin_mocks.h and umock_end_mocks.h would be included. Done means the headers toggle mock mode and report errors for repeated begins, unmatched ends, and repeated ends.

Written by the indexing model from the issue text.