Cache variable BUILD_SHARED_LIBS

CHANGES.md

@@ -1,5 +1,13 @@
 # Changes
 
+## 0.9.1
+
+- (backwards incompatible) Add CMake cache variable `BUILD_SHARED_LIBS`.
+  The default is a static library for mobile (Android and iOS), and a
+  shared library otherwise; that is the same pattern followed by opencv.
+  The variable should be explicitly set to `ON` if a shared library must
+  be created, and `OFF` if a static library must be created.
+
 ## 0.9.0
 
 - Forked to the DkML repository on GitLab.
@@ -11,7 +19,9 @@
 - Wrap macro parameters in the `capnp_use(x)` macro. Passes clang-tidy (not
   a false positive)
 - Add POSITION_INDEPENDENT_CODE to CapnC::Runtime
-- Add C_CAPNPROTO_ENABLE_INSTALL with default ON to enable cmake --install
+- Add C_CAPNPROTO_ENABLE_INSTALL with default ON to turn off and on
+  installation of targets and files in `cmake --install`, especially for when
+  this project is used within a FetchContent() command.
 
 ## 0.3 (632f0d73a1f4a03026b5e4727386b9fe3ec6e00e)
 

CMakeLists.txt

@@ -24,13 +24,12 @@ if(APPLE)
     set(CMAKE_MACOSX_RPATH OFF)
 endif()
 
-# Boilerplate DK CMAKE PROJ 2023-05-17.2
-if(BUILD_SHARED_LIBS)
-    # SHARED is implied by BUILD_SHARED_LIBS=ON
-    set(linkage)
-else()
-    set(linkage STATIC)
+# Boilerplate DK CMAKE PROJ 2023-09-25.1
+set(default_build_shared)
+if(NOT (ANDROID OR IOS))
+    set(default_build_shared ON)
 endif()
+option(BUILD_SHARED_LIBS "Build shared libraries (.dll/.so) instead of static ones (.lib/.a)" ${default_build_shared})
 
 # Build hygiene: Tools for keeping the source code clean. By default
 # we try to enforce build hygiene.
@@ -52,7 +51,7 @@ if(NOT BUILD_HYGIENE STREQUAL DISABLED)
             ${find_program_args})
 endif()
 
-add_library(CapnC_Runtime ${linkage}
+add_library(CapnC_Runtime
         lib/capn.c
         lib/capn-malloc.c
         lib/capn-stream.c