-Dtests=true fails to build on BSDs due to -I= instead of -I or -isystem

[jbeich]

Regressed by d0cf159. Doesn't affect -Dtests=false (default) builds.

$ meson setup -Dtests=true /tmp/neatvnc_build
$ meson compile -C /tmp/neatvnc_build
[...]
FAILED: test/pixels.p/test-pixels.c.o
cc -Itest/pixels.p -Itest -Itest -Iinclude -I/usr/local/include/pixman-1 -I=/usr/local/include -fcolor-diagnostics -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -std=gnu11 -O0 -g '-DPROJECT_VERSION="0.5.0"' -D_GNU_SOURCE -fvisibility=hidden -Wmissing-prototypes '-DGIT_VERSION="v0.5.0-1-gcd23192 (freebsd)"' -MD -MQ test/pixels.p/test-pixels.c.o -MF test/pixels.p/test-pixels.c.o.d -o test/pixels.p/test-pixels.c.o -c test/test-pixels.c
test/test-pixels.c:8:10: fatal error: 'libdrm/drm_fourcc.h' file not found
#include <libdrm/drm_fourcc.h>
         ^~~~~~~~~~~~~~~~~~~~~
1 error generated.
FAILED: test/pixels.p/.._src_pixels.c.o
cc -Itest/pixels.p -Itest -Itest -Iinclude -I/usr/local/include/pixman-1 -I=/usr/local/include -fcolor-diagnostics -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -std=gnu11 -O0 -g '-DPROJECT_VERSION="0.5.0"' -D_GNU_SOURCE -fvisibility=hidden -Wmissing-prototypes '-DGIT_VERSION="v0.5.0-1-gcd23192 (freebsd)"' -MD -MQ test/pixels.p/.._src_pixels.c.o -MF test/pixels.p/.._src_pixels.c.o.d -o test/pixels.p/.._src_pixels.c.o -c src/pixels.c
src/pixels.c:21:10: fatal error: 'libdrm/drm_fourcc.h' file not found
#include <libdrm/drm_fourcc.h>
         ^~~~~~~~~~~~~~~~~~~~~
1 error generated.
ninja: build stopped: subcommand failed.

[jbeich]

Note, on FreeBSD cross-compilation is often done via poudriere (as used by official package builders) which already isolates host from target. I don't have/use Linux, so don't understand "host leakage" being fixed by d0cf159.

[jbeich]

Generally, -isystem is preferred over -I when using includes from (system) packages due to the way search paths are ordered and out-of-scope warnings are hidden. I don't know what -I= does as it appears missing from GCC manpage and is too short/has special characters for Google/DuckDuckGo.

[any1]

The man page entry for -I says the following:

If dir begins with = or $SYSROOT, then the = or $SYSROOT is replaced by the sysroot prefix; see --sysrootand -isysroot.

I can see how it's hard to find because the string -I= doesn't appear anywhere in the document.

Could it be that the sysroot of your environment is set to an unexpected value?

[jbeich]

Could it be that the sysroot of your environment is set to an unexpected value?

I don't use sysroot.

$ cat a.c
#include <libdrm/drm_fourcc.h>
int main() {}

$ cc -I=/usr/local/include a.c
a.c:1:10: fatal error: 'libdrm/drm_fourcc.h' file not found
#include <libdrm/drm_fourcc.h>
         ^~~~~~~~~~~~~~~~~~~~~
1 error generated.

If Meson is run with CFLAGS+=-v then during build I see

ignoring nonexistent directory "=/usr/local/include"

However, when building without tests something else (e.g., gnutls, libturbojpeg) adds -I/usr/local/include.

[any1]

Hmm, I had assumed that if gcc wasn't built with sysroot, the = would be replaced with an empty string. That's probably not the case. If you set --sysroot=/, does that do anything?

[jbeich]

If you set --sysroot=/, does that do anything?

Makes -I=/usr/local/include work like -I/usr/local/include. Tested both Clang (default) and GCC.

[jbeich]

If you need to get libdrm flags from pkg-config without overriding search order try using include_type: system like emersion/libliftoff@009570230398.

[any1]

I think this might be the solution: https://mesonbuild.com/Reference-manual_returned_dep.html#deppartial_dependency

[any1]

I pushed a partial_dependency based patch to master. Does that solve the problem?

[jbeich]

Does that solve the problem?

Not yet due to missing libdrm_inc in test/meson.build

FAILED: test/pixels.p/test-pixels.c.o
cc -Itest/pixels.p -Itest -Itest -Iinclude -I/usr/local/include/pixman-1 -fcolor-diagnostics -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -std=gnu11 -O0 -g '-DPROJECT_VERSION="0.5.0"' -D_GNU_SOURCE -fvisibility=hidden -Wmissing-prototypes '-DGIT_VERSION="v0.5.0-2-gf4f8f0b (master)"' -MD -MQ test/pixels.p/test-pixels.c.o -MF test/pixels.p/test-pixels.c.o.d -o test/pixels.p/test-pixels.c.o -c test/test-pixels.c
test/test-pixels.c:8:10: fatal error: 'libdrm/drm_fourcc.h' file not found
#include <libdrm/drm_fourcc.h>
         ^~~~~~~~~~~~~~~~~~~~~
1 error generated.
FAILED: test/pixels.p/.._src_pixels.c.o
cc -Itest/pixels.p -Itest -Itest -Iinclude -I/usr/local/include/pixman-1 -fcolor-diagnostics -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -std=gnu11 -O0 -g '-DPROJECT_VERSION="0.5.0"' -D_GNU_SOURCE -fvisi
bility=hidden -Wmissing-prototypes '-DGIT_VERSION="v0.5.0-2-gf4f8f0b (master)"' -MD -MQ test/pixels.p/.._src_pixels.c.o -MF test/pixels.p/.._src_pixels.c.o.d -o test/pixels.p/.._src_pixels.c.o -c src/pixels.c
src/pixels.c:21:10: fatal error: 'libdrm/drm_fourcc.h' file not found
#include <libdrm/drm_fourcc.h>
         ^~~~~~~~~~~~~~~~~~~~~
1 error generated.

[any1]

Ahh, that was a bit hasty of me. Fixed now.

[jbeich]

Builds fine now, so packaged.

[any1]

Thanks!