bash-5.1.8 does not compile anymore on HP-UX due to invalid shell syntax

[Osipov, Michael (LDA IT PLM)]

Folks,

this is basically the same issue as I reported in readline: 
https://lists.gnu.org/archive/html/bug-readline/2021-08/msg00000.html

The bad hunk seems not to be POSIX shell compliant. Both vars are set 
for me on HP-UX because the expansion is incomplete. According to [1] it 
has to be $(GCC:+..} and not $(GCC+..}. I have changed ./configure 
locally and it works with /bin/sh.

I assume that this should also work on any other POSIX compliant shell.

Michael

[1] 
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_02