Improve libinotify detection on BSDs

[tleedjarv]

No description provided.

[gdt]

I tried to read the code and construct the test program build line:

ocamlc -ccopt "-I/usr/pkg/include" -cclib "-L/usr/pkg/lib -Wl,-rpath/usr/pkg/lib -linoti" inotifytest__.c && echo OK

and then I munged the lib to misspell (pasted above) and it still passed. It does fail without the -I part.

I think what's going on is that this is compiling the .c, but there is no link step so the unresolved symbol is not objected to.
In autoconf speak, I think we need AC_TRY_LINK, and not just AC_TRY_COMPILE.

[tleedjarv]

I think what's going on is that this is compiling the .c, but there is no link step so the unresolved symbol is not objected to. In autoconf speak, I think we need AC_TRY_LINK, and not just AC_TRY_COMPILE.

You're right... but now that I think about it, there's no need for this test at all. I wrote it before relying on pkg-conf. If we require pkg-conf then we don't need to do this test compile/link at all and can just use the output of pkg-conf directly, no?

[gdt]

There's pkg-config succeeding, which means there's a .pc file, and then there's actually being able to link. I will see what the norms are in the autoconf world, but my gut reaction is to try to link.

(Separately, autoconf also prints out "checking for foo...yes" sorts of things and it would help debugging to have a yes/no about libinotify, sort of Checking for libinotify...[yes/no], followed by [Enabling fsmonitor/inotify.]/[Disabling fsmonitor.])

[gdt]

I looked at two random programs that use pkg-config via autoconf, and they both just believe the output. Perhaps it is wise to use --exists first, and if true, just set flags based on --cflags/--libs.

[tleedjarv]

I looked at two random programs that use pkg-config via autoconf, and they both just believe the output. Perhaps it is wise to use --exists first, and if true, just set flags based on --cflags/--libs.

Simplifying sounds like a good idea. Let's do just that. If this backfires in the future, we can always revisit this.

[gdt]

Thanks for the multiple iterations. I have tested via pkgsrc-wip (before the latest if clarification but that's good enough) and it works both ways, with libinotify apparently present and apparently not present.