Six new unary elementwise operators in Subgraph API

- Abs
- Bankers' Rounding
- Ceiling
- Floor
- Negate
- Square

PiperOrigin-RevId: 315649679
diff --git a/BUILD.bazel b/BUILD.bazel
index ac12b52..8de69a6 100644
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -72,24 +72,30 @@
 ]
 
 SUBGRAPH_SRCS = [
+    "src/subgraph/abs.c",
     "src/subgraph/add2.c",
     "src/subgraph/argmax-pooling-2d.c",
     "src/subgraph/average-pooling-2d.c",
+    "src/subgraph/bankers-rounding.c",
+    "src/subgraph/ceiling.c",
     "src/subgraph/clamp.c",
     "src/subgraph/convolution-2d.c",
     "src/subgraph/deconvolution-2d.c",
     "src/subgraph/depthwise-convolution-2d.c",
     "src/subgraph/divide.c",
     "src/subgraph/fully-connected.c",
+    "src/subgraph/floor.c",
     "src/subgraph/hardswish.c",
     "src/subgraph/max-pooling-2d.c",
     "src/subgraph/maximum2.c",
     "src/subgraph/minimum2.c",
     "src/subgraph/multiply2.c",
+    "src/subgraph/negate.c",
     "src/subgraph/prelu.c",
     "src/subgraph/sigmoid.c",
     "src/subgraph/softmax.c",
     "src/subgraph/static-constant-pad.c",
+    "src/subgraph/square.c",
     "src/subgraph/squared-difference.c",
     "src/subgraph/subtract.c",
     "src/subgraph/unpooling-2d.c",