gnucash master: Fix quotes on Windows.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/576fc9b5 (commit)
	from  https://github.com/Gnucash/gnucash/commit/90e1e2d1 (commit)



commit 576fc9b52cc2fd7d444c445630d0e91a9b1834ee
Author: John Ralls <jralls at ceridwen.us>
Date:   Sun Mar 19 10:28:30 2023 -0700

    Fix quotes on Windows.
    
    Boost process wchar_t conversion chokes if it's fed an empty string.
    This would happen when the user had no alphavantage key. Separate
    the process invocation to not present the empty value to boost process.



Summary of changes:
 libgnucash/app-utils/gnc-quotes.cpp | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)