ADD: PCRE superbuild (dep of SWIG)

CMake/External_pcre.cmake

+message(STATUS "Setup pcre...")
+
+set(proj PCRE)
+
+set(DEFAULT_USE_SYSTEM_PCRE  OFF)
+
+option(USE_SYSTEM_PCRE "  Use a system build of pcre." ${DEFAULT_USE_SYSTEM_PCRE})
+mark_as_advanced(USE_SYSTEM_PCRE)
+
+if(USE_SYSTEM_PCRE)
+  message(STATUS "  Using pcre system version")
+else()
+  set(${proj}_DEPENDENCIES)
+  set(PCRE_SB_BUILD_DIR ${CMAKE_BINARY_DIR}/${proj}/build)
+  set(PCRE_SB_SRC ${CMAKE_BINARY_DIR}/${proj}/src/${proj})
+  
+  if(MSVC)
+    # TODO ?
+  else()
+    ExternalProject_Add(${proj}
+      PREFIX ${proj}
+      URL "http://sourceforge.net/projects/pcre/files/pcre/8.36/pcre-8.36.tar.gz/download"
+      URL_MD5 ff7b4bb14e355f04885cf18ff4125c98
+      BINARY_DIR ${PCRE_SB_BUILD_DIR}
+      INSTALL_DIR ${CMAKE_INSTALL_PREFIX}
+      CONFIGURE_COMMAND
+        ${PCRE_SB_BUILD_DIR}/configure
+        --prefix=${CMAKE_INSTALL_PREFIX}
+      BUILD_COMMAND $(MAKE)
+      INSTALL_COMMAND $(MAKE) install
+      DEPENDS ${${proj}_DEPENDENCIES}
+      )
+    
+    ExternalProject_Add_Step(${proj} copy_source
+      COMMAND ${CMAKE_COMMAND} -E copy_directory 
+        ${PCRE_SB_SRC} ${PCRE_SB_BUILD_DIR}
+      DEPENDEES patch update
+      DEPENDERS configure
+      )
+    
+  endif()
+  
+  message(STATUS "  Using pcre SuperBuild version")
+endif()