gnu: Add abseil-cpp.

* gnu/packages/cpp.scm (abseil-cpp): New variable.

Signed-off-by: Pierre Neidhardt <mail@ambrevar.xyz>

gnu/packages/cpp.scm

@@ -7,6 +7,7 @@
 ;;; Copyright © 2019 Pierre Neidhardt <mail@ambrevar.xyz>
 ;;; Copyright © 2019 Jan Wielkiewicz <tona_kosmicznego_smiecia@interia.pl>
 ;;; Copyright © 2020 Nicolò Balzarotti <nicolo@nixo.xyz>
+;;; Copyright © 2020 Roel Janssen <roel@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -439,3 +440,47 @@ (define-public tweeny
 other values of screen objects, by setting their values as the tween starting
 point and then, after each tween step, plugging back the result.")
     (license license:expat)))
+
+(define-public abseil-cpp
+  (package
+    (name "abseil-cpp")
+    (version "20200225")
+    (source (origin
+              (method git-fetch)
+              (uri (git-reference
+                    (url "https://github.com/abseil/abseil-cpp.git")
+                    (commit version)))
+              (file-name (git-file-name name version))
+              (sha256
+               (base32
+                "0wb04pszzrl39ny1pz9jvvq8lbbm355dd60jspcyqfwxnk6njgd1"))))
+    (build-system cmake-build-system)
+    (arguments
+     `(#:configure-flags (list "-DBUILD_SHARED_LIBS=ON"
+                               "-DABSL_RUN_TESTS=ON"
+                               ;; Needed, else we get errors like:
+                               ;;
+                               ;; ld: CMakeFiles/absl_periodic_sampler_test.dir/internal/periodic_sampler_test.cc.o:
+                               ;;   undefined reference to symbol '_ZN7testing4Mock16UnregisterLockedEPNS_8internal25UntypedFunctionMockerBaseE'
+                               ;; ld: /gnu/store/bxapb1f1l8frjpbjckk3zdxhmcig3xzk-googletest-1.10.0/lib/libgmock.so:
+                               ;;   error adding symbols: DSO missing from command line
+                               ;; collect2: error: ld returned 1 exit status
+                               "-DCMAKE_EXE_LINKER_FLAGS=-lgtest -lpthread -lgmock")
+       #:phases
+       (modify-phases %standard-phases
+         (add-before 'configure 'remove-gtest-check
+           ;; The CMakeLists fails to find our googletest for some reason, but
+           ;; it works nonetheless.
+           (lambda _
+             (substitute* "CMakeLists.txt"
+               (("check_target\\(gtest\\)") "")
+               (("check_target\\(gtest_main\\)") "")
+               (("check_target\\(gmock\\)") "")))))))
+    (native-inputs
+     `(("googletest" ,googletest)))
+    (home-page "https://abseil.io")
+    (synopsis "Augmented C++ standard library")
+    (description "Abseil is a collection of C++ library code designed to
+augment the C++ standard library.  The Abseil library code is collected from
+Google's C++ code base.")
+    (license license:asl2.0)))