gtest: Update to 1.13.0 and build shared libs

Tests are broken, see google/googletest#3442

devel/gtest/Portfile

@@ -6,8 +6,9 @@ PortGroup       compiler_blacklist_versions 1.0
 PortGroup       cmake 1.1
 PortGroup       legacysupport 1.1
 
-github.setup    google googletest 1.12.1 release-
-revision        1
+github.setup    google googletest 1.13.0 v
+github.tarball_from archive
+revision        0
 
 name            gtest
 categories      devel
@@ -24,9 +25,9 @@ long_description \
                 fatal and non-fatal failures, various options for \
                 running the tests, and XML test report generation.
 
-checksums       rmd160  3991930354c07c75875fba519d7aa6b12eba21a8 \
-                sha256  a28fa459c227d0bd97acc9c18503870b24eabaa69056c7f637144747c469e66a \
-                size    854915
+checksums       rmd160  a9c9160e28d4d2573f07235f05e25ae1cad8f261 \
+                sha256  ad7fdba11ea011c1d925b3289cf4af2c66a352e18d4c7264392fead75e919363 \
+                size    862871
 
 patchfiles      patch-add-gtest-version.diff
 
@@ -43,7 +44,15 @@ compiler.cxx_standard   2014
 cmake.set_cxx_standard  yes
 
 configure.optflags      -g
-configure.args-append   -Dgtest_build_tests=ON
+configure.args-append   -Dgtest_build_tests=ON \
+                        -DBUILD_SHARED_LIBS=OFF
+
+# Tests are broken for shared libs, see
+# https://github.com/google/googletest/issues/3442
+variant shared_libs description "Build dynamic library" {
+configure.args-replace  -DBUILD_SHARED_LIBS=OFF \
+                        -DBUILD_SHARED_LIBS=ON
+}
 
 # Prevent MacPorts headers from being used. They're not needed since
 # googletest has no dependencies, and if a different version of googletest