dev-libs/libwacom-1.0 fails to link with LTO

[bitthief]

Hi,

Ever since libwacom got bumped to version 1.0 about 1 week ago, I am seeing a link failure with the default flags:

* CFLAGS='-march=native -O3 -fgraphite-identity -floop-nest-optimize -fdevirtualize-at-ltrans -fipa-pta -fno-semantic-interposition -flto=12 -fuse-linker-plugin -pipe -falign-functions=32 -Wl,-O1 -Wl,--as-needed -Wl,--hash-style=gnu'
* CXXFLAGS='-march=native -O3 -fgraphite-identity -floop-nest-optimize -fdevirtualize-at-ltrans -fipa-pta -fno-semantic-interposition -flto=12 -fuse-linker-plugin -pipe -falign-functions=32 -Wl,-O1 -Wl,--as-needed -Wl,--hash-style=gnu'
* FFLAGS='-march=native -O3 -fgraphite-identity -floop-nest-optimize -fdevirtualize-at-ltrans -fipa-pta -fno-semantic-interposition -flto=12 -fuse-linker-plugin -pipe -falign-functions=32 -Wl,-O1 -Wl,--as-needed -Wl,--hash-style=gnu'
* FCFLAGS='-march=native -O3 -fgraphite-identity -floop-nest-optimize -fdevirtualize-at-ltrans -fipa-pta -fno-semantic-interposition -flto=12 -fuse-linker-plugin -pipe -falign-functions=32 -Wl,-O1 -Wl,--as-needed -Wl,--hash-style=gnu'
* F77FLAGS='-march=native -O3 -fgraphite-identity -floop-nest-optimize -fdevirtualize-at-ltrans -fipa-pta -fno-semantic-interposition -flto=12 -fuse-linker-plugin -pipe -falign-functions=32 -Wl,-O1 -Wl,--as-needed -Wl,--hash-style=gnu'
* LDFLAGS='-Wl,-O1 -Wl,--as-needed -Wl,--hash-style=gnu -march=native -O3 -fgraphite-identity -floop-nest-optimize -fdevirtualize-at-ltrans -fipa-pta -fno-semantic-interposition -flto=12 -fuse-linker-plugin -pipe -falign-functions=32'
* MAKEOPTS='-j12 -l16'

The following build log shows the problem:

libtool: link: x86_64-pc-linux-gnu-gcc -I/usr/include/gudev-1.0 -I/usr/lib64/libffi-3.3_rc0/include -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -march=native -O3 -fgraphite-identity -floop-nest-optimize -fdevirtualize-at-ltrans -fipa-pta -fno-semantic-interposition -flto=12 -fuse-linker-plugin -pipe -falign-functions=32 -Wl,-O1 -Wl,--hash-style=gnu -Wl,-O1 -Wl,--hash-style=gnu -march=native -O3 -fgraphite-identity -floop-nest-optimize -fdevirtualize-at-ltrans -fipa-pta -fno-semantic-interposition -flto=12 -fuse-linker-plugin -pipe -falign-functions=32 -o test-tablet-validity test_tablet_validity-test-tablet-validity.o  -Wl,--as-needed ../libwacom/.libs/libwacom.so -lgudev-1.0 -lgobject-2.0 -lglib-2.0 -ldl -Wl,-rpath -Wl,/var/tmp/portage/dev-libs/libwacom-1.0/work/libwacom-1.0/libwacom/.libs
/usr/lib/gcc/x86_64-pc-linux-gnu/9.2.0/../../../../x86_64-pc-linux-gnu/bin/ld: /var/tmp/portage/dev-libs/libwacom-1.0/temp/test-deprecated.ajTaKa.ltrans0.ltrans.o: in function `main':
<artificial>:(.text.startup+0x9d): undefined reference to `libwacom_match_destroy@LIBWACOM_0.33'
/usr/lib/gcc/x86_64-pc-linux-gnu/9.2.0/../../../../x86_64-pc-linux-gnu/bin/ld: <artificial>:(.text.startup+0xaa): undefined reference to `libwacom_match_new@LIBWACOM_0.33'
/usr/lib/gcc/x86_64-pc-linux-gnu/9.2.0/../../../../x86_64-pc-linux-gnu/bin/ld: <artificial>:(.text.startup+0xb7): undefined reference to `libwacom_error_set@LIBWACOM_0.33'
/usr/lib/gcc/x86_64-pc-linux-gnu/9.2.0/../../../../x86_64-pc-linux-gnu/bin/ld: <artificial>:(.text.startup+0xbe): undefined reference to `libwacom_stylus_destroy@LIBWACOM_0.33'
/usr/lib/gcc/x86_64-pc-linux-gnu/9.2.0/../../../../x86_64-pc-linux-gnu/bin/ld: <artificial>:(.text.startup+0xc7): undefined reference to `libwacom_update_match@LIBWACOM_0.33'
collect2: error: ld returned 1 exit status
make[2]: *** [Makefile:665: test-deprecated] Error 1
make[2]: *** Waiting for unfinished jobs....
make[2]: Leaving directory '/var/tmp/portage/dev-libs/libwacom-1.0/work/libwacom-1.0/test'
make[1]: *** [Makefile:462: all-recursive] Error 1
make[1]: Leaving directory '/var/tmp/portage/dev-libs/libwacom-1.0/work/libwacom-1.0'

This has also been reported upstream, but no solution is provided:
linuxwacom/libwacom#152

I think it'd be wise to disable LTO for the package for now?