Autoconf script will break if proj version jumps to double digit

[jeroen]

Trying to make cross compiling work, I found that there are several places in your configure where you are version checking PROJ using cut -c 1 or cut -c 1,2 which assumes both major and minor have exactly 1 digit.

So if proj ever jumps to version 10, then your configure script treats this as version 1. This also applies to lwgeom.

While we are at it:

The script seems to lookup the proj_version several times using a mix of methods. When cross compiling we should be assuming the version that is given by pkgconfig:

sf/configure.ac

Lines 355 to 356 in 1ea4d8b

	PROJ_VERSION=`${PROJ_CONFIG} --modversion`
	PROJV1=`echo "${PROJ_VERSION}" | cut -c 1`

We cannot run test programs like this in a cross environment:

sf/configure.ac

Lines 468 to 470 in 1ea4d8b

	${CC} ${CFLAGS} ${CPPFLAGS} -o proj_conf_test proj_conf_test.c ${PROJ_LIBS}
	proj_version=`./proj_conf_test`

So perhaps the script can also be simplified a bit lookup the proj version only once, and only fall back on running a test program if no pkg-config --modversion version was found ?

[edzer]

Great thinking - thanks for the PR!

[edzer]

Still fails for wasm - any ideas what to do?

[jeroen]

Looking at errors.txt that the configure generates, the problem seems to linking errors at this line:

https://github.com/r-spatial/lwgeom/blob/7cd821b7aaf63b6bf149a8f97981b8d98336795b/configure.ac#L148

Which are caused by a duplicated -lsqlite3:

wasm-ld: error: duplicate symbol: sqlite3_initialize
>>> defined in /opt/webr/wasm/lib/libsqlite3.a(sqlite3.o)
>>> defined in /opt/webr/wasm/lib/libsqlite3.a(sqlite3.o)

wasm-ld: error: duplicate symbol: sqlite3_malloc
>>> defined in /opt/webr/wasm/lib/libsqlite3.a(sqlite3.o)
>>> defined in /opt/webr/wasm/lib/libsqlite3.a(sqlite3.o)

...

The wasm linker is a bit more pedantic than other linkers, and doesn't allow duplicated flags. The problem is that pkg-config proj --libs already contains -lsqlite3 so in this the line linked above you shouldn't add -lsqlite3 if this is already contained in ${LIBS}.

# pkg-config --libs proj
-lproj -lstdc++ -lsqlite3 -lpthread -ltiff -lcurl -ldl

[edzer]

That now passes, but hangs on geos; I looked at the successful wasm build of sf, but could not find the configure step being executed there (which has the same code as the thing that now hangs lwgeom wasm build).