The Solaris build fails to build libarrow_bundled_dependencies.a because of some mismatch of arguments to the ar command:
[ 19%] Bundling /export/home/XnknpBn/Rtemp/RtmpBOhxfH/file66df7a592ae4/release/libarrow_bundled_dependencies.a
gmake: Entering directory '/export/home/XnknpBn/Rtemp/RtmpBOhxfH/file66df7a592ae4'
usage: ar -d[-SvV] archive file ...
ar -m[-abiSvV] [posname] archive file ...
ar -p[-vV][-sS] archive [file ...]
ar -q[-cuvSV] [-abi] [posname] [file ...]
ar -r[-cuvSV] [-abi] [posname] [file ...]
ar -t[-vV][-sS] archive [file ...]
ar -x[-vV][-sSCT] archive [file ...]
gmake: *** [src/arrow/CMakeFiles/arrow_bundled_dependencies.dir/build.make:61: release/libarrow_bundled_dependencies.a] Error 1
If ARROW_PARQUET=OFF (
ARROW-11735), the only dependencies to bundle are re2 and utf8proc. So we could either fix the ar invocation, or we could make re2 and utf8proc optional. Build-wise, they are optional, but we have some tests that call the string kernels, and we'd need to know that they should be skipped (i.e. another option in skip_if_not_available().