libstdc++: Relocate c++config.h from include/ to libstdc++ to preserve upstream integrity

- Add c++config.h to improve libstdc++ configuration support
- Update CMakeLists.txt and libsupc++.defs to integrate the new config header
- Remove the obsolete 0001-libsupc-Add-missing-header-files.patch to clean up the codebase

These changes enhance the maintainability and portability of the C++ standard library and simplify the build process.

libs/libxx/libstdc++/CMakeLists.txt

@@ -45,9 +45,6 @@ if(CONFIG_LIBSUPCXX)
             ""
             TEST_COMMAND
             ""
-        PATCH_COMMAND
-          patch -p1 -d ${CMAKE_CURRENT_LIST_DIR}/libstdc++ <
-          ${CMAKE_CURRENT_LIST_DIR}/0001-libsupc-Add-missing-header-files.patch
         DOWNLOAD_NO_PROGRESS true
         TIMEOUT 30)
 
@@ -81,6 +78,7 @@ if(CONFIG_LIBSUPCXX)
   set(BITSDIR ${CMAKE_BINARY_DIR}/include/c++/bits)
 
   # Copy libsupc++ headers
+  file(COPY ${CMAKE_CURRENT_LIST_DIR}/c++config.h DESTINATION ${INCDIR}/bits)
   file(COPY ${SUPDIR}/compare DESTINATION ${CXXDIR})
   file(COPY ${SUPDIR}/exception DESTINATION ${CXXDIR})
   file(COPY ${SUPDIR}/initializer_list DESTINATION ${CXXDIR})

libs/libxx/libstdc++/libsupc++.defs

@@ -31,7 +31,6 @@ libstdc++-v3.tar.gz:
 libstdc++/libstdc++: libstdc++-v3.tar.gz
 	$(Q) mkdir -p $@
 	$(Q) tar -xzf $< -C $@
-	$(Q) patch -p1 < libstdc++/0001-libsupc-Add-missing-header-files.patch -d $@
 endif
 
 C++DIR = $(TOPDIR)/include/c++
@@ -50,6 +49,7 @@ $(BITSDIR): libstdc++/libstdc++
 	$(Q) mkdir -p $(BITSDIR)
 
 copy_headers: $(BITSDIR)
+	$(Q) cp libstdc++/c++config.h $(INCDIR)/bits
 	$(Q) cp $(SUPDIR)/compare $(C++DIR)
 	$(Q) cp $(SUPDIR)/exception $(C++DIR)
 	$(Q) cp $(SUPDIR)/initializer_list $(C++DIR)
@@ -75,6 +75,7 @@ context:: copy_headers
 
 distclean::
 	$(call DELDIR, $(BITSDIR))
+	$(call DELFILE, $(INCDIR)/bits/c++config.h)
 ifeq ($(wildcard libstdc++/libstdc++/.git),)
 	$(call DELDIR, libstdc++)
 	$(call DELFILE, libstdc++.tar.gz)