dev-cpp/scnlib: new package, add 2.0.0

Signed-off-by: Steffen Winter <steffen.winter@proton.me>

dev-cpp/scnlib/files/scnlib-2.0.0-no-external-test-deps.patch

@@ -0,0 +1,59 @@
+diff --git a/cmake/dependencies.cmake b/cmake/dependencies.cmake
+index ae2832b..c250eff 100644
+--- a/cmake/dependencies.cmake
++++ b/cmake/dependencies.cmake
+@@ -4,41 +4,10 @@ set(SCN_OPTIONAL_DEPENDENCIES "")
+ 
+ if (SCN_TESTS)
+     # GTest
+-
+-    FetchContent_Declare(
+-            googletest
+-            GIT_REPOSITORY https://github.com/google/googletest.git
+-            GIT_TAG main
+-            GIT_SHALLOW TRUE
+-    )
+-
+-    # gtest CMake does some flag overriding we don't want, and it's also quite heavy
+-    # Do it manually
+-
+-    set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+-
+-    FetchContent_GetProperties(googletest)
+-    if (NOT googletest)
+-        FetchContent_Populate(googletest)
+-    endif ()
+-
+-    find_package(Threads)
+-
+-    add_library(scn_gtest
+-            "${googletest_SOURCE_DIR}/googletest/src/gtest-all.cc"
+-            "${googletest_SOURCE_DIR}/googlemock/src/gmock-all.cc"
+-    )
+-    target_include_directories(scn_gtest SYSTEM
+-            PUBLIC
+-            "${googletest_SOURCE_DIR}/googletest/include"
+-            "${googletest_SOURCE_DIR}/googlemock/include"
+-            PRIVATE
+-            "${googletest_SOURCE_DIR}/googletest"
+-            "${googletest_SOURCE_DIR}/googlemock"
+-    )
+-    target_link_libraries(scn_gtest PRIVATE Threads::Threads)
+-    target_compile_features(scn_gtest PUBLIC cxx_std_17)
+-    target_compile_options(scn_gtest PRIVATE $<$<CXX_COMPILER_ID:GNU>: -Wno-psabi>)
++    find_package(GTest REQUIRED)
++    add_library(scn_gtest INTERFACE)
++    target_link_libraries(scn_gtest INTERFACE GTest::GTest)
++    target_compile_features(scn_gtest INTERFACE cxx_std_17)
+ endif ()
+ 
+ if (SCN_BENCHMARKS)
+@@ -158,8 +127,3 @@ if (SCN_REGEX_BACKEND STREQUAL "re2")
+     set(SCN_REGEX_BACKEND_TARGET re2::re2)
+ endif ()
+ 
+-# make available
+-
+-FetchContent_MakeAvailable(
+-        ${SCN_OPTIONAL_DEPENDENCIES}
+-)