COMP: Make the Sphinx linkcheck optional

The linkcheck can sporatically timeout and fail. Make it optional to
avoid false positives in CI.

Author: thewtex

CMake/FindSphinx.cmake

@@ -64,6 +64,7 @@ option( SPHINX_EPUB_OUTPUT "Build HTML pages with additional information for bui
 option( SPHINX_LATEX_OUTPUT "Build LaTeX sources that can be compiled to a PDF document using pdflatex." OFF )
 option( SPHINX_MAN_OUTPUT "Build manual pages in groff format for UNIX systems." OFF )
 option( SPHINX_TEXT_OUTPUT "Build plain text files." OFF )
+option( SPHINX_LINKCHECK "Create a target that will check HTTP links." OFF )
 
 
 mark_as_advanced(
@@ -77,6 +78,7 @@ mark_as_advanced(
   SPHINX_LATEX_OUTPUT
   SPHINX_MAN_OUTPUT
   SPHINX_TEXT_OUTPUT
+  SPHINX_LINKCHECK
 )
 
 function( Sphinx_add_target target_name builder conf source destination )
@@ -152,7 +154,7 @@ function( Sphinx_add_targets target_base_name conf source base_destination )
     add_dependencies( ${target_base_name}_text ${_dependencies} )
   endif()
 
-  if( ${BUILD_TESTING} )
+  if( ${SPHINX_LINKCHECK} )
     sphinx_add_target( ${target_base_name}_linkcheck linkcheck ${conf} ${source} ${base_destination}/linkcheck )
 
     add_dependencies( ${target_base_name}_linkcheck ${_dependencies} )

Superbuild/Superbuild.cmake

@@ -94,6 +94,7 @@ if(BUILD_DOCUMENTATION)
     "-DSPHINX_MAN_OUTPUT:BOOL=${SPHINX_MAN_OUTPUT}"
     "-DSPHINX_QTHELP_OUTPUT:BOOL=${SPHINX_QTHELP_OUTPUT}"
     "-DSPHINX_TEXT_OUTPUT:BOOL=${SPHINX_TEXT_OUTPUT}"
+    "-DSPHINX_LINKCHECK:BOOL=${SPHINX_LINKCHECK}"
     )
 endif()