cmake: Build training tools also on Linux and macOS

This enables CI tests for the code in src/training on Linux and macOS.

Signed-off-by: Stefan Weil <[email protected]>

Author: stweil

src/training/CMakeLists.txt

@@ -2,10 +2,6 @@
 # tesseract
 #
 
-if (NOT CPPAN_BUILD AND NOT (WIN32 OR CYGWIN))
-    return()
-endif()
-
 if (CPPAN_BUILD)
     set(ICU_FOUND 1)
 endif()