BUG #19095: Test if function exit() is used fail when linked static

The following bug has been logged on the website:

Bug reference:      19095
Logged by:          Torsten Rupp
Email address:      torsten.rupp@gmx.net
PostgreSQL version: 15.14
Operating system:   Linux
Description:

Note: occur from version 15.14 or newer.

In src/interfaces/libpq/Makefile is a test if the function "exit()" (or in
general: a function exists with the name part "exit") is used:

libpq-refs-stamp: $(shlib)
ifneq ($(enable_coverage), yes)
ifeq (,$(filter aix solaris,$(PORTNAME)))
        @if nm -A -u $< 2>/dev/null | grep -v __cxa_atexit | grep exit; then
\
                echo 'libpq must not be calling any function which invokes
exit'; exit 1; \
        fi
endif
endif

This test fail if libpq is linked static to an application when e. g.
libcrypto is also linked static into libpq which add indirectly a call to
"pthread_exit()".

Possible fix: exclude pthread_exit(), too (like __cxa_atexit), e.g.:

libpq-refs-stamp: $(shlib)
ifneq ($(enable_coverage), yes)
ifeq (,$(filter aix solaris,$(PORTNAME)))
        @if nm -A -u $< 2>/dev/null | grep -v __cxa_atexit | grep -v
pthread_exit | grep exit; then \
                echo 'libpq must not be calling any function which invokes
exit'; exit 1; \
        fi
endif
endif