DCMTK

DCMTK currently supports four alternative libraries for handling character set conversions:

• GNU iconv
• libc iconv, i.e. an iconv() function available in libc
• ICU
• DCMTK's built-in oficonv module, which was introduced with DCMTK 3.6.8, which is the new default

The desired library can be selected by passing a CMake variable:

cmake -DDCMTK_ENABLE_CHARSET_CONVERSION:STRING=DCMTK_CHARSET_CONVERSION_ICONV 

It has been observed that on a Linux platform where the GNU iconv library is not installed,
and cmake is called as shown above, DCMTK is compiled with stdlibc iconv support, but the unit tests
for GNU libiconv are executed, causing test failures in three test cases.

Apparently, despite falling back to libc iconv, CMake retains some #defines indicating that GNU libiconv has been used.

This should be checked, and fixed. Manually selecting GNU libiconv should cause a CMake error if GNU libiconv is not found.