v4.7.1

This release contains no code changes.
It enhances library symbol visibility with GCC and compilation issues with recent GCC versions

Enhancements (C API)

    - OCILIB internal and public symbols management
        * For static library:
            - All private symbols that can have local scope are now declared static
            - All private non static symbols are now prefixed with "Ocilib" to avoid collisions 
        * For shared library:
            - No change for Windows platform as __declspec(dllimport) and  __declspec(dllexport) were already handled
            - When using GNUC compatible compiler:
                - all public  symbols are now declared with __attribute__ ((visibility ("default")))
                - all private symbols are now delcared with __attribute__ ((visibility ("hidden")))
                - Configure script will automatically add the compiler flag "-fvisibility=hidden"
    
    - OCILIB compiles now without any warnings when using GNUC with flags -Wall -Wextra -pedantic

Fixes (C API)

    - Issue 242:  Fixed strings.h conflict with recent GCC versions
    - Issue 243 : Fixed compiling ocilib directly from repository on non Windows systems (while using distribution archive was OK)
    - Issue 245 : Fixed ocilib shared library symbols visibility (Linux/Unix)

Changes (C API)

    - Removed useless old macros for mapping lib C string function to ansi or wide char versions (ostrXXX)
    - Removed symbols ocisprintf(), ocistrdup(), ocistrcasecmp(), ociwcsdup(), ociwcscasecmp() from OCILIB shared library

Miscellaneous

    - Updated compilers for MS Windows prebuilt binaries
        * VS2019 16.7.6 for 32/64 bit DLLs