ARROW-4207: [Gandiva] [GLib] Add support for IfNode

[shiro615]

No description provided.

[codecov-io]

Codecov Report

Merging #3354 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3354      +/-   ##
==========================================
+ Coverage   88.36%   88.37%   +<.01%     
==========================================
  Files         557      557              
  Lines       73560    73562       +2     
==========================================
+ Hits        65001    65008       +7     
+ Misses       8450     8449       -1     
+ Partials      109      105       -4

Impacted Files	Coverage Δ
go/arrow/math/uint64_sse4_amd64.go	0% <0%> (-100%)	⬇️
go/arrow/math/float64_sse4_amd64.go	0% <0%> (-100%)	⬇️
go/arrow/memory/memory_sse4_amd64.go	0% <0%> (-100%)	⬇️
go/arrow/math/int64_sse4_amd64.go	0% <0%> (-100%)	⬇️
cpp/src/plasma/store.cc	91.32% <0%> (-0.78%)	⬇️
cpp/src/arrow/vendored/xxhash/xxhash.c	73.6% <0%> (-0.51%)	⬇️
go/arrow/math/float64_amd64.go	33.33% <0%> (ø)	⬆️
go/arrow/math/int64_amd64.go	33.33% <0%> (ø)	⬆️
go/arrow/math/uint64_amd64.go	33.33% <0%> (ø)	⬆️
cpp/src/arrow/util/bpacking.h	99.84% <0%> (ø)	⬆️
... and 6 more

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[kou]

Thanks!
Could you check my comment?

[kou]

Rust build failure is unrelated. I'll merge this.