Re: 8.2beta1 crash possibly in libpq

Hi Magnus,

I finally got to the bottom of this - it seems that the flags being
passed to MingW's linker were incorrect, but instead of erroring out it
decided to create a corrupt executable. Here is the command line that
was being used to link the pgsql2shp.exe executable, along with the
associated auto-import warning:

gcc -g -Wall -I.. -DUSE_ICONV -DUSE_VERSION=82 shpopen.o dbfopen.o
getopt.o PQunescapeBytea.o pgsql2shp.o -liconv
C:/msys/1.0/home/mca/pg82/REL-8~1.2BE/lib/libpq.dll -o pgsql2shp.exe
Info: resolving _PQntuples by linking to __imp__PQntuples (auto-import)

Note that libpq.dll is referenced directly with -l which I believe
should be an invalid syntax. This produces a corrupt executable that
crashes whenever PQntuples is accessed. On the other hand, a correct
executable can be realised by linking like this:

gcc -g -Wall -I.. -DUSE_ICONV -DUSE_VERSION=82 shpopen.o dbfopen.o
getopt.o PQunescapeBytea.o pgsql2shp.o -liconv
-LC:/msys/1.0/home/mca/pg82/REL-8~1.2BE/lib -lpq -o pgsql2shp.exe

Note there is no auto-import warning, and the use of -L and -l is how I
would expect. In actual fact, the incorrect link line was being produced
by an error in the configure.in script, so this won't be a scenario that
most people will experience.

The executables linked using the second method now work properly without
crashing during regression. The big mystery is that the command line
used to link the executables has been like that for several versions
now, and I have absolutely no idea why it only triggered this failure
when being linked against 8.2beta1 when it works perfectly on 8.1 and
8.0, and also why only PQntuples was affected.

Kind regards,

Mark.