CMake support

- initial cmake support
- downgrade cmake requirement to 2.8.12
- factorize cmake test flags / libs options
- refactor test / library under helpers functions, follow bazel's style
- Add fix for MSVC and Windows support ( thx @patrikfors )
- Switch to default "add_subdirectory()" usage mode
- add CMake/README.md for instructions
- add header-only cmake target generator
- map absl target to absl:: namespace

absl/types/CMakeLists.txt

@@ -0,0 +1,153 @@
+#
+# Copyright 2017 The Abseil Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+list(APPEND TYPES_PUBLIC_HEADERS
+  "any.h"
+  "bad_any_cast.h"
+  "bad_optional_access.h"
+  "optional.h"
+  "span.h"
+)
+
+
+
+list(APPEND BAD_ANY_CAST_SRC
+  "bad_any_cast.cc"
+  ${TYPES_PUBLIC_HEADERS}
+)
+set(BAD_ANY_CAST_PUBLIC_LIBRARIES absl::base)
+
+absl_library(
+  TARGET
+    absl_bad_any_cast
+  SOURCES
+    ${BAD_ANY_CAST_SRC}
+  PUBLIC_LIBRARIES
+    ${BAD_ANY_CAST_PUBLIC_LIBRARIES}
+)
+
+
+
+set(OPTIONAL_SRC "optional.cc")
+set(OPTIONAL_PUBLIC_LIBRARIES absl::base)
+
+absl_library(
+  TARGET
+    absl_optional
+  SOURCES
+    ${OPTIONAL_SRC}
+  PUBLIC_LIBRARIES
+    ${OPTIONAL_PUBLIC_LIBRARIES}
+)
+
+
+set(BAD_OPTIONAL_ACCESS_SRC "bad_optional_access.cc")
+set(BAD_OPTIONAL_ACCESS_LIBRARIES absl::base)
+
+absl_library(
+  TARGET
+    absl_bad_optional_access
+  SOURCES
+    ${BAD_OPTIONAL_ACCESS_SRC}
+  PUBLIC_LIBRARIES
+    ${BAD_OPTIONAL_ACCESS_PUBLIC_LIBRARIES}
+)
+
+
+
+absl_header_library(
+  TARGET
+    absl_types
+  PUBLIC_LIBRARIES
+    absl_optional absl_bad_any_cast absl_bad_optional_access
+  EXPORT_NAME
+    types
+)
+
+#
+## TESTS
+#
+
+
+# test any_test
+set(ANY_TEST_SRC "any_test.cc")
+set(ANY_TEST_PUBLIC_LIBRARIES absl::base absl_throw_delegate absl_bad_any_cast test_instance_tracker_lib)
+
+absl_test(
+  TARGET
+    any_test
+  SOURCES
+    ${ANY_TEST_SRC}
+  PUBLIC_LIBRARIES
+    ${ANY_TEST_PUBLIC_LIBRARIES}
+  PRIVATE_COMPILE_FLAGS
+    ${ABSL_EXCEPTIONS_FLAG}
+)
+
+
+# test any_test_noexceptions
+absl_test(
+  TARGET
+    any_test_noexceptions
+  SOURCES
+    ${ANY_TEST_SRC}
+  PUBLIC_LIBRARIES
+    ${ANY_TEST_PUBLIC_LIBRARIES}
+)
+
+
+# test span_test
+set(SPAN_TEST_SRC "span_test.cc")
+set(SPAN_TEST_PUBLIC_LIBRARIES absl::base absl::strings absl_throw_delegate absl_bad_any_cast test_instance_tracker_lib)
+
+absl_test(
+  TARGET
+    span_test
+  SOURCES
+    ${SPAN_TEST_SRC}
+  PUBLIC_LIBRARIES
+    ${SPAN_TEST_PUBLIC_LIBRARIES}
+  PRIVATE_COMPILE_FLAGS
+    ${ABSL_EXCEPTIONS_FLAG}
+)
+
+
+# test span_test_noexceptions
+absl_test(
+  TARGET
+    span_test_noexceptions
+  SOURCES
+    ${SPAN_TEST_SRC}
+  PUBLIC_LIBRARIES
+    ${SPAN_TEST_PUBLIC_LIBRARIES}
+)
+
+
+
+# test optional_test
+set(OPTIONAL_TEST_SRC "optional_test.cc")
+set(OPTIONAL_TEST_PUBLIC_LIBRARIES absl::base absl_throw_delegate absl_optional bad_optional_access)
+
+absl_test(
+  TARGET
+    optional_test
+  SOURCES
+    ${OPTIONAL_TEST_SRC}
+  PUBLIC_LIBRARIES
+    ${OPTIONAL_TEST_PUBLIC_LIBRARIES}
+)
+
+