bootstrap: Add KWSys Encoding and FStream

Run the KWSYS_STL_HAS_WSTRING platform test and configure the result.
Configure the Encoding and FStream header files and build the sources.
On Windows, build EncodingC.c with KWSYS_ENCODING_DEFAULT_CODEPAGE=CP_ACP.

bootstrap

@@ -318,11 +318,13 @@ CMAKE_C_SOURCES="\
 
 if ${cmake_system_mingw}; then
   KWSYS_C_SOURCES="\
+    EncodingC \
     ProcessWin32 \
     String \
     System"
 else
   KWSYS_C_SOURCES="\
+    EncodingC \
     ProcessUNIX \
     String \
     System"
@@ -330,6 +332,7 @@ fi
 
 KWSYS_CXX_SOURCES="\
   Directory \
+  EncodingCXX \
   Glob \
   RegularExpression \
   SystemTools"
@@ -337,6 +340,9 @@ KWSYS_CXX_SOURCES="\
 KWSYS_FILES="\
   auto_ptr.hxx \
   Directory.hxx \
+  Encoding.h \
+  Encoding.hxx \
+  FStream.hxx \
   Glob.hxx \
   Process.h \
   RegularExpression.hxx \
@@ -479,6 +485,7 @@ cmake_kwsys_config_replace_string ()
                 s/@KWSYS_STL_HAS_ALLOCATOR_REBIND@/${KWSYS_STL_HAS_ALLOCATOR_REBIND}/g;
                 s/@KWSYS_STL_HAS_ALLOCATOR_MAX_SIZE_ARGUMENT@/${KWSYS_STL_HAS_ALLOCATOR_MAX_SIZE_ARGUMENT}/g;
                 s/@KWSYS_STL_HAS_ALLOCATOR_OBJECTS@/${KWSYS_STL_HAS_ALLOCATOR_OBJECTS}/g;
+                s/@KWSYS_STL_HAS_WSTRING@/${KWSYS_STL_HAS_WSTRING}/g;
                 s/@KWSYS_CXX_HAS_CSTDDEF@/${KWSYS_CXX_HAS_CSTDDEF}/g;
                 s/@KWSYS_CXX_HAS_NULL_TEMPLATE_ARGS@/${KWSYS_CXX_HAS_NULL_TEMPLATE_ARGS}/g;
                 s/@KWSYS_CXX_HAS_MEMBER_TEMPLATES@/${KWSYS_CXX_HAS_MEMBER_TEMPLATES}/g;
@@ -1123,6 +1130,7 @@ KWSYS_STL_HAS_ALLOCATOR_NONTEMPLATE=0
 KWSYS_STL_HAS_ALLOCATOR_REBIND=0
 KWSYS_STL_HAS_ALLOCATOR_MAX_SIZE_ARGUMENT=0
 KWSYS_STL_HAS_ALLOCATOR_OBJECTS=0
+KWSYS_STL_HAS_WSTRING=0
 KWSYS_CXX_HAS_SETENV=0
 KWSYS_CXX_HAS_UNSETENV=0
 KWSYS_CXX_HAS_ENVIRON_IN_STDLIB_H=0
@@ -1309,6 +1317,15 @@ else
   echo "${cmake_cxx_compiler} does not have stl containers supporting allocator objects"
 fi
 
+if cmake_try_run "${cmake_cxx_compiler}" \
+  "${cmake_cxx_flags} -DTEST_KWSYS_STL_HAS_WSTRING -DKWSYS_STL_HAVE_STD=${KWSYS_STL_HAVE_STD}" \
+  "${cmake_source_dir}/Source/kwsys/kwsysPlatformTestsCXX.cxx" >> cmake_bootstrap.log 2>&1; then
+  KWSYS_STL_HAS_WSTRING=1
+  echo "${cmake_cxx_compiler} has stl wstring"
+else
+  echo "${cmake_cxx_compiler} does not have stl wstring"
+fi
+
 if cmake_try_run "${cmake_cxx_compiler}" \
   "${cmake_cxx_flags} -DTEST_KWSYS_CXX_HAS_CSTDDEF" \
   "${cmake_source_dir}/Source/kwsys/kwsysPlatformTestsCXX.cxx" >> cmake_bootstrap.log 2>&1; then
@@ -1516,6 +1533,9 @@ if [ "x${cmake_cxx_flags}" != "x" ]; then
 fi
 
 cmake_c_flags_String="-DKWSYS_STRING_C"
+if ${cmake_system_mingw}; then
+  cmake_c_flags_EncodingC="-DKWSYS_ENCODING_DEFAULT_CODEPAGE=CP_ACP"
+fi
 cmake_cxx_flags_SystemTools="
   -DKWSYS_CXX_HAS_SETENV=${KWSYS_CXX_HAS_SETENV}
   -DKWSYS_CXX_HAS_UNSETENV=${KWSYS_CXX_HAS_UNSETENV}