COMP: provide option to disable use of float exception macros

Emscripten and WASI throw "undefined symbol" error on float
exception macros such as FE_INVALID. Provide a flag to
disable the use of such macros when building ITK/DCMTK with
unconventional compilers such as emscripten and wasi.

Modules/ThirdParty/DCMTK/CMakeLists.txt

@@ -290,6 +290,12 @@ endforeach()
   if(CMAKE_CROSSCOMPILING_EMULATOR)
     list(APPEND _cross_compiling_flags -DCMAKE_CROSSCOMPILING_EMULATOR:FILEPATH=${CMAKE_CROSSCOMPILING_EMULATOR})
   endif()
+
+  set(DCMTK_CXX_FLAGS ${CMAKE_CXX_FLAGS})
+  if(NO_FLOAT_EXCEPTIONS)
+    string(APPEND DCMTK_CXX_FLAGS " -DNO_FLOAT_EXCEPTIONS")
+  endif()
+
   itk_download_attempt_check(${DCMTK_EPNAME})
   ExternalProject_Add(${DCMTK_EPNAME}
     GIT_REPOSITORY ${DCMTK_GIT_REPOSITORY}
@@ -328,6 +334,7 @@ endforeach()
     -DCMAKE_INSTALL_LIBDIR:PATH=${CMAKE_INSTALL_LIBDIR}
     -DCMAKE_INSTALL_BINDIR:PATH=${CMAKE_INSTALL_BINDIR}
     -DDCMTK_ENABLE_BUILTIN_OFICONV_DATA:BOOL=${DCMTK_ENABLE_BUILTIN_OFICONV_DATA}
+    -DCMAKE_CXX_FLAGS:STRING=${DCMTK_CXX_FLAGS}
     ${CHARSET_CONVERSION_ARGS}
     DEPENDS ${JPEG_DEPENDENCY} ${PNG_DEPENDENCY} ${TIFF_DEPENDENCY} ${ICU_DEPENDENCY}
     BUILD_BYPRODUCTS ${DCMTK_BYPRODUCTS}