dev-cpp/gsl: use system catch for USE="test".

Closes: https://bugs.gentoo.org/636828
Closes: gentoo#6431
Package-Manager: Portage-2.3.13, Repoman-2.3.3

dev-cpp/gsl/Manifest

@@ -1 +1 @@
-DIST gsl-0_pre20171105.tar.gz 55870 SHA256 5adc4b4ba53102099f63b898da161469a854d4fd47e90195421fbe8bd8b50352 SHA512 0db9cae9af710c45f66d1e2b73e2002f921876d400165d13dbe9ede7aa9335249458a9f97d4eda4cff0b3a5ceebb6ef84b631310921011fedee8776fcec89e6a WHIRLPOOL 98e26057646f6be4cc6632901b2b45c5e46218e9048cd64561f7f118ee0e8feadeca3ca66a0b73a36a431b666fe7946c6f864dbcf97296bae3945b2350dcf2e5
+DIST gsl-0_pre20171105.tar.gz 55870 BLAKE2B cc26a8a304a65cd6a487d22369b5b23169e07144a7629388fffdbf263619c0849f00efcc1a072408e3e89dd933e3309c15049d0fec30de07267b5b693c5c9657 SHA512 0db9cae9af710c45f66d1e2b73e2002f921876d400165d13dbe9ede7aa9335249458a9f97d4eda4cff0b3a5ceebb6ef84b631310921011fedee8776fcec89e6a

dev-cpp/gsl/files/gsl-0_pre20171105-use_system_catch-636828.patch

@@ -0,0 +1,31 @@
+# Disable upstreams catch download, we always want to use the system installed 
+# version. Gentoo bug 636828.
+
+diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
+index 86ce5a4..9b7d4f7 100644
+--- a/tests/CMakeLists.txt
++++ b/tests/CMakeLists.txt
+@@ -10,21 +10,8 @@ list(APPEND CATCH_CMAKE_ARGS
+ "-DNO_SELFTEST=true"
+ )
+
+-if(GIT_FOUND)
+- # add catch
+- ExternalProject_Add(
+- catch
+- PREFIX ${CMAKE_BINARY_DIR}/catch
+- GIT_REPOSITORY https://github.com/catchorg/Catch2.git
+- GIT_TAG v2.0.1
+- CMAKE_ARGS ${CATCH_CMAKE_ARGS}
+- LOG_DOWNLOAD 1
+- UPDATE_DISCONNECTED 1
+- )
+-else()
+- # assume catch is installed in a system directory
+- add_custom_target(catch)
+-endif()
++# assume catch is installed in a system directory
++add_custom_target(catch)
+
+ # this interface adds compile options to how the tests are run
+ # please try to keep entries ordered =)