Continue CMake support improvement

- Update documentation
- Remove type target
- Remove typos
- simplify target
- improve 1-1 matchign with Bazel targets

CMake/README.md

@@ -4,37 +4,64 @@
 
 ### Recommended usage : incorporate Abseil into an  CMake project
 
-    We recommended to build and use abseil in the same way than googletest
-    ( https://github.com/google/googletest/blob/master/googletest/README.md )
+  For API / ABI compatibility reasons, it is recommended to build
+  and use abseil in a subdirectory of your project or as an embedded
+  dependency
 
-    * Download abseil and copy it in a sub-directory in your project.
+  This is similar to the recommended usage of the googletest framework
+  ( https://github.com/google/googletest/blob/master/googletest/README.md )
 
-    * Or add abseil as a git-submodule in your project
+  Build and use step-by-step
 
-    You can then use the cmake `add_subdirectory()` command to include
-    abseil directly and use the abseil targets in your project.
 
-    Abseil requires CCTZ and the googletest framework. Consequently, 
+  1- Download abseil and copy it in a sub-directory in your project.
+      or add abseil as a git-submodule in your project
+
+  2- If not done yet, download and copy in your project the two dependencies of
+      abseil `cctz` and `googletest`
+
+    * cctz  https://github.com/google/cctz
+    * googletest https://github.com/google/googletest
+
+  3- You can then use the cmake command `add_subdirectory()` to include
+  abseil directly and use the abseil targets in your project.
+
+    Note: Abseil requires CCTZ and the googletest framework. Consequently,
     the targets  `gtest`, `gtest_main`, `gmock` and `cctz` need
-    to be declared in your project before including abseil with `add_subdirectory`. 
-    You can find instructions on how to get and build these projects at these 
-    URL :
-        * cctz  https://github.com/google/cctz
-        * googletest https://github.com/google/googletest
+    to be declared in your project before including abseil with `add_subdirectory`.
 
-    
 
-    Here is a short CMakeLists.txt example of a possible project file 
-    using abseil
-    
-    project(my_project)
-    
-    add_subdirectory(googletest)
-    add_subdirectory(cctz)    
-    add_subdirectory(abseil-cpp)
+  4- Add the absl:: target you wish to use to the `target_link_libraries()`
+    section of your executable or of your library
+
+
+      Here is a short CMakeLists.txt example of a possible project file
+      using abseil
+
+      project(my_project)
+
+      add_subdirectory(googletest)
+      add_subdirectory(cctz)
+      add_subdirectory(abseil-cpp)
+
+      add_executable(my_exe source.cpp)
+      target_link_libraries(my_exe absl::base absl::synchronization absl::strings)
+
+
+    You will find here a non exhaustive list of absl public targets
+
+      absl::base
+      absl::algorithm
+      absl::container
+      absl::debugging
+      absl::memory
+      absl::meta
+      absl::numeric
+      absl::strings
+      absl::synchronization
+      absl::time
+      absl::utility
 
-    add_executable(my_exe source.cpp)
-    target_link_libraries(my_exe base synchronization strings)