Fix linux build: undefined std:string_view

Pop 'mesh' library c++ stranderd to c++17
Add required <string_view> header

src/Mod/Mesh/App/CMakeLists.txt

@@ -399,6 +399,8 @@ endif ()
 
 add_library(Mesh SHARED ${Core_SRCS} ${WildMagic4_SRCS} ${Mesh_SRCS})
 target_link_libraries(Mesh ${Mesh_LIBS})
+set_target_properties(Mesh PROPERTIES CXX_STANDARD_REQUIRED ON)
+set_target_properties(Mesh PROPERTIES CXX_STANDARD 17)
 
 
 SET_BIN_DIR(Mesh Mesh /Mod/Mesh)

src/Mod/Mesh/App/Core/MeshIO.cpp

@@ -46,6 +46,7 @@
 #include <sstream>
 #include <iomanip>
 #include <algorithm>
+#include <string_view>
 #include <boost/regex.hpp>
 #include <boost/algorithm/string.hpp>
 #include <boost/lexical_cast.hpp>

src/Mod/PartDesign/App/json.hpp

@@ -43,6 +43,7 @@ SOFTWARE.
 #include <memory> // unique_ptr
 #include <numeric> // accumulate
 #include <string> // string, stoi, to_string
+#include <string_view> // string_view
 #include <utility> // declval, forward, move, pair, swap
 #include <vector> // vector