chore(deps): upgrade abseil to 20210324.2 (#6664)

Fixes: #6627

This version of Abseil adds proper pkgconfig support, so we no longer
need dynamically compute the Abseil .so files to link with, instead we
can just list the pkg-config deps that we "require" from Abseil. Indeed,
our old way of computing the libraries no longer works, so this change
was required in the same PR as the Abseil upgrade.

Author: devjgm

bazel/google_cloud_cpp_deps.bzl

@@ -41,11 +41,11 @@ def google_cloud_cpp_deps():
     if "com_google_absl" not in native.existing_rules():
         http_archive(
             name = "com_google_absl",
-            strip_prefix = "abseil-cpp-20200923.3",
+            strip_prefix = "abseil-cpp-20210324.2",
             urls = [
-                "https://github.com/abseil/abseil-cpp/archive/20200923.3.tar.gz",
+                "https://github.com/abseil/abseil-cpp/archive/20210324.2.tar.gz",
             ],
-            sha256 = "ebe2ad1480d27383e4bf4211e2ca2ef312d5e6a09eba869fd2e8a5c5d553ded2",
+            sha256 = "59b862f50e710277f8ede96f083a5bb8d7c9595376146838b9580be90374ee1f",
         )
 
     # Load a version of googletest that we know works.

ci/abi-dumps/google_cloud_cpp_bigtable.expected.abi.dump.gz

@@ -71,7 +71,7 @@ ENV PATH=/usr/local/bin:${PATH}
 
 # ```bash
 WORKDIR /var/tmp/build/abseil-cpp
-RUN curl -sSL https://github.com/abseil/abseil-cpp/archive/20200923.3.tar.gz | \
+RUN curl -sSL https://github.com/abseil/abseil-cpp/archive/20210324.2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     sed -i 's/^#define ABSL_OPTION_USE_\(.*\) 2/#define ABSL_OPTION_USE_\1 0/' "absl/base/options.h" && \
     cmake \

ci/abi-dumps/google_cloud_cpp_common.expected.abi.dump.gz

@@ -46,7 +46,7 @@ ENV PATH=/usr/local/bin:${PATH}
 
 # ```bash
 WORKDIR /var/tmp/build/abseil-cpp
-RUN curl -sSL https://github.com/abseil/abseil-cpp/archive/20200923.3.tar.gz | \
+RUN curl -sSL https://github.com/abseil/abseil-cpp/archive/20210324.2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     sed -i 's/^#define ABSL_OPTION_USE_\(.*\) 2/#define ABSL_OPTION_USE_\1 0/' "absl/base/options.h" && \
     cmake \

ci/abi-dumps/google_cloud_cpp_grpc_utils.expected.abi.dump.gz

@@ -42,7 +42,7 @@ RUN apt-get update && \
 
 # ```bash
 WORKDIR /var/tmp/build/abseil-cpp
-RUN curl -sSL https://github.com/abseil/abseil-cpp/archive/20200923.3.tar.gz | \
+RUN curl -sSL https://github.com/abseil/abseil-cpp/archive/20210324.2.tar.gz | \
     tar -xzf - --strip-components=1 && \
     sed -i 's/^#define ABSL_OPTION_USE_\(.*\) 2/#define ABSL_OPTION_USE_\1 0/' "absl/base/options.h" && \
     cmake \