static libpq (and other libraries) overwritten on aix

Hi,

I was hacking in making aix work with the meson patchset last night when I
noticed this delightful bit:

gmake -C src/interfaces/libpq
...

rm -f libpq.a
ar crs libpq.a fe-auth-scram.o fe-connect.o fe-exec.o fe-lobj.o fe-misc.o fe-print.o fe-protocol3.o fe-secure.o
fe-trace.olegacy-pqsignal.o libpq-events.o pqexpbuffer.o fe-auth.o
 
touch libpq.a

( echo '#! libpq.so.5'; gawk '/^[^#]/ {printf "%s\n",$1}'
/home/andres/src/postgres/build-ac/../src/interfaces/libpq/exports.txt) >libpq.exp
 
gcc -maix64 -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Werror=vla -Wendif-labels
-Wmissing-format-attribute-Wimplicit-fallthrough=3 -Wformat-security -fno-strict-aliasing -fwrapv
-fexcess-precision=standard-Wno-format-truncation -O2 -pthread -D_REENTRANT -D_THREAD_SAFE  -o libpq.so.5 libpq.a
-Wl,-bE:libpq.exp-L../../../src/port -L../../../src/common -lpgcommon_shlib -lpgport_shlib -Wl,-bbigtoc
-Wl,-blibpath:'/usr/local/pgsql/lib:/usr/lib:/lib' -Wl,-bnoentry -Wl,-H512 -Wl,-bM:SRE -lm
 

rm -f libpq.a
ar crs libpq.a libpq.so.5


we first create a static library libpq.a as normal, but then we overwrite it
with the special aix way of packing up shared libraries, by packing them up in
a static library.  That part is correct, it's apparently the easiest way of
getting applications to link to shared libraries on AIX (I think the
-Wl,-bM:SRE is relevant for ensuring it'll be a dynamic link, rather than a
static one).

This likely has been going on for approximately forever.

Two questions:
1) Do we continue building static libraries for libpq etc?
2) Do we care about static libraries not suriving on AIX? There could also be
   a race in the buildrules leading to sometimes static libs sometimes shared
   libs winning, I think.

Greetings,

Andres Freund