newt: Extend link tables filter

So far for link time generated tables only exact section name
was added to filter like in this example:

pkg.link_tables:
    - foo

would generate link_tables.ld.h with following content
        __foo_start__ = .;
        KEEP(*(.foo))
        __foo_end__ = .;

Now additional filter will be added
        __foo_start__ = .;
        KEEP(*(.foo))
        KEEP(*(SORT(.foo.*)))
        __foo_end__ = .;

This is general rule for many sections like .text or .data

This is specifically required for xc32 compiler that
adds variable name to section by itself even though
__attribute__((section, "foo")) is used and arm gcc
treats name in attribute verbatim and not as prefix.

Author: kasjer

newt/builder/extcmd.go

@@ -189,6 +189,7 @@ func getLinkTableEntry(name string) string {
 
 	entry := indent + "__" + name + "_start__ = .;\n" +
 		indent + "KEEP(*(." + name + "))\n" +
+		indent + "KEEP(*(SORT(." + name + ".*)))\n" +
 		indent + "__" + name + "_end__ = .;\n\n"
 
 	return entry