Move TeX symbol decoding into the lexer (bug #39831). * libinterp/Makefile.am (BUILT_SOURCES): Add corefcn/oct-tex-symbols.cc. (BUILT_DISTFILES): Add corefcn/oct-tex-lexer.ll and corefcn/oct-tex-symbols.cc. (EXTRA_DIST): Add corefcn/oct-tex-lexer.in.ll and corefcn/oct-tex-symbols.in. (ULT_DIST_SRC): Filter out corefcn/oct-tex-lexer.ll from DIST_SRC and add corefcn/oct-tex-lexer.in.ll instead. (CLEAN_FILES): Add corefcn/oct-tex-parser.output. * libinterp/corefcn/modules.mk (corefcn/oct-tex-lexer.ll, corefcn/oct-tex-symbols.cc): New rules to build the TeX lexer. (corefcn/txt-eng.cc): Add dependency on corefcn/oct-tex-symbols.cc. * libinterp/corefcn/oct-tex-lexer.in.ll: Renamed from oct-tex.lexer.ll. Remove COMMAND state. Remove ID regex. Replace rules for symbols with tag @SYMBOL_RULES@. * libinterp/corefcn/oct-tex-parser.yy (ID, CMD, identifier): Remove tokens. (SYM, sym): New token and value. (symbol_element): Build from SYM. * libinterp/corefcn/oct-tex-symbols.in: New file with supported TeX symbols and corresponding codes (unicode and MS symbols). * libinterp/corefcn/txt-eng.h (class text_element_symbol): Make it inherit from text_element. (text_element_symbol::code): Removed member. (text_element_symbol::symbol): New member. (text_element_symbol::text_element_symbol): Adapt constructor. (text_element_symbol::get_symbol): New method. (text_element_symbol::get_symbol_code): Make const. * libinterp/corefcn/txt-eng.cc (symbol_names, symbol_codes): Remove static variables, now auto-generated from oct-tex-symbols.in. (oct-tex-symbols.cc): New include. (text_element_symbol::get_symbol_code): Change implementation to simply index into auto-generated symbol_codes array. * libinterp/corefcn/txt-eng-ft.cc (ft_render::visit(text_element_symbol)): Don't use text_element_symbol::string_value(), use text_element_symbol::get_symbol() instead.