CMake: Allow using BUILD_SHARED_LIBS to choose static/shared libs (#655)

By convention projects using CMake which can build either static or
shared libraries use a BUILD_SHARED_LIBS flag to allow selecting between
both: the add_library() command automatically switches between both using
this variable when the library kind is not passed to add_library(). It
is also usual to expose the BUILD_SHARED_LIBS as an user-facing setting
with the option() command.

This way, the following will both work as expected:

   % cmake -DBUILD_SHARED_LIBS=OFF ...
   % cmake -DBUILS_SHARED_LIBS=ON ...

This is helpful for distributions which need (or want) to build only
static libraries.

1 files changed, 15 insertions, 31 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e4a03aa..7ee3973 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,6 +11,8 @@ cmake_minimum_required(VERSION 2.8.6)
 cmake_policy(SET CMP0048 NEW)
 project(brotli C)
 
+option(BUILD_SHARED_LIBS "Build shared libraries" ON)
+
 if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
   message(STATUS "Setting build type to Release as none was specified.")
   set(CMAKE_BUILD_TYPE "Release" CACHE STRING "Choose the type of build." FORCE)
@@ -136,10 +138,6 @@ set(BROTLI_LIBRARIES_CORE brotlienc brotlidec brotlicommon)
 set(BROTLI_LIBRARIES ${BROTLI_LIBRARIES_CORE} ${LIBM_LIBRARY})
 mark_as_advanced(BROTLI_LIBRARIES)
 
-set(BROTLI_LIBRARIES_CORE_STATIC brotlienc-static brotlidec-static brotlicommon-static)
-set(BROTLI_LIBRARIES_STATIC ${BROTLI_LIBRARIES_CORE_STATIC} ${LIBM_LIBRARY})
-mark_as_advanced(BROTLI_LIBRARIES_STATIC)
-
 if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
   add_definitions(-DOS_LINUX)
 elseif(${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD")
@@ -162,29 +160,25 @@ transform_sources_list("scripts/sources.lst" "${CMAKE_CURRENT_BINARY_DIR}/source
 include("${CMAKE_CURRENT_BINARY_DIR}/sources.lst.cmake")
 
 if(BROTLI_EMSCRIPTEN)
-  set(BROTLI_SHARED_LIBS "")
-else()
-  set(BROTLI_SHARED_LIBS brotlicommon brotlidec brotlienc)
-  add_library(brotlicommon SHARED ${BROTLI_COMMON_C})
-  add_library(brotlidec SHARED ${BROTLI_DEC_C})
-  add_library(brotlienc SHARED ${BROTLI_ENC_C})
+  set(BUILD_SHARED_LIBS OFF)
 endif()
 
-set(BROTLI_STATIC_LIBS brotlicommon-static brotlidec-static brotlienc-static)
-add_library(brotlicommon-static STATIC ${BROTLI_COMMON_C})
-add_library(brotlidec-static STATIC ${BROTLI_DEC_C})
-add_library(brotlienc-static STATIC ${BROTLI_ENC_C})
+add_library(brotlicommon ${BROTLI_COMMON_C})
+add_library(brotlidec ${BROTLI_DEC_C})
+add_library(brotlienc ${BROTLI_ENC_C})
 
 # Older CMake versions does not understand INCLUDE_DIRECTORIES property.
 include_directories(${BROTLI_INCLUDE_DIRS})
 
-foreach(lib IN LISTS BROTLI_SHARED_LIBS)
-  target_compile_definitions(${lib} PUBLIC "BROTLI_SHARED_COMPILATION" )
-  string(TOUPPER "${lib}" LIB)
-  set_target_properties (${lib} PROPERTIES DEFINE_SYMBOL "${LIB}_SHARED_COMPILATION")
-endforeach()
+if(BUILD_SHARED_LIBS)
+  foreach(lib ${BROTLI_LIBRARIES_CORE})
+    target_compile_definitions(${lib} PUBLIC "BROTLI_SHARED_COMPILATION" )
+    string(TOUPPER "${lib}" LIB)
+    set_target_properties (${lib} PROPERTIES DEFINE_SYMBOL "${LIB}_SHARED_COMPILATION")
+  endforeach()
+endif()
 
-foreach(lib IN LISTS BROTLI_SHARED_LIBS BROTLI_STATIC_LIBS)
+foreach(lib ${BROTLI_LIBRARIES_CORE})
   target_link_libraries(${lib} ${LIBM_LIBRARY})
   set_property(TARGET ${lib} APPEND PROPERTY INCLUDE_DIRECTORIES ${BROTLI_INCLUDE_DIRS})
   set_target_properties(${lib} PROPERTIES
@@ -201,9 +195,6 @@ target_link_libraries(brotlidec brotlicommon)
 target_link_libraries(brotlienc brotlicommon)
 endif()
 
-target_link_libraries(brotlidec-static brotlicommon-static)
-target_link_libraries(brotlienc-static brotlicommon-static)
-
 # For projects stuck on older versions of CMake, this will set the
 # BROTLI_INCLUDE_DIRS and BROTLI_LIBRARIES variables so they still
 # have a relatively easy way to use Brotli:
@@ -217,7 +208,7 @@ endif()
 
 # Build the brotli executable
 add_executable(brotli ${BROTLI_CLI_C})
-target_link_libraries(brotli ${BROTLI_LIBRARIES_STATIC})
+target_link_libraries(brotli ${BROTLI_LIBRARIES})
 
 # Installation
 if(NOT BROTLI_BUNDLED_MODE)
@@ -236,13 +227,6 @@ if(NOT BROTLI_BUNDLED_MODE)
   endif()  # BROTLI_EMSCRIPTEN
 
   install(
-    TARGETS ${BROTLI_LIBRARIES_CORE_STATIC}
-    ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
-    LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
-    RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
-  )
-
-  install(
     DIRECTORY ${BROTLI_INCLUDE_DIRS}/brotli
     DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}"
   )