[Bug fortran/93461] Bogus "symbol is already defined" with long subroutine names in submodule

[abensonca at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93461

--- Comment #2 from Andrew Benson <abensonca at gmail dot com> ---
The problem occurs because GFC_MAX_MANGLED_SYMBOL_LEN is set to 
GFC_MAX_SYMBOL_LEN*2+4, which is sufficient for a module name plus function
name 
(plus the additional "_"'s that get prepended), but insufficient if a submodule 
name is included. The name then gets truncated and can lead to two different 
functions having the same (truncated) symbol name.

The fix is to increase this length to GFC_MAX_SYMBOL_LEN*3+5 - which allows for 
the submodule name plus the "." added between module and submodule names.

Patch attached.