cmake support for specifying specific (static/shared) target to link for zlib, zstd, etc

Author: Nigel Stewart

CMakeLists.txt

@@ -35,10 +35,17 @@ function(boost_iostreams_option name description package version found target) #
 
 endfunction()
 
-boost_iostreams_option(BOOST_IOSTREAMS_ENABLE_ZLIB "Boost.Iostreams: Enable ZLIB support" ZLIB "" ZLIB_FOUND ZLIB::ZLIB src/zlib.cpp src/gzip.cpp)
-boost_iostreams_option(BOOST_IOSTREAMS_ENABLE_BZIP2 "Boost.Iostreams: Enable BZip2 support" BZip2 "" BZIP2_FOUND BZip2::BZip2 src/bzip2.cpp)
-boost_iostreams_option(BOOST_IOSTREAMS_ENABLE_LZMA "Boost.Iostreams: Enable LZMA support" LibLZMA "" LIBLZMA_FOUND LibLZMA::LibLZMA src/lzma.cpp)
-boost_iostreams_option(BOOST_IOSTREAMS_ENABLE_ZSTD "Boost.Iostreams: Enable Zstd support" zstd "1.0" zstd_FOUND zstd::libzstd_shared src/zstd.cpp)
+# Linking shared libraries by default but can be overridden as needed
+
+set(BOOST_IOSTREAMS_TARGET_ZLIB ZLIB::ZLIB)
+set(BOOST_IOSTREAMS_TARGET_BZIP2 BZip2::BZip2)
+set(BOOST_IOSTREAMS_TARGET_LZMA LibLZMA::LibLZMA)
+set(BOOST_IOSTREAMS_TARGET_ZSTD zstd::libzstd_shared)
+
+boost_iostreams_option(BOOST_IOSTREAMS_ENABLE_ZLIB "Boost.Iostreams: Enable ZLIB support" ZLIB "" ZLIB_FOUND ${BOOST_IOSTREAMS_TARGET_ZLIB} src/zlib.cpp src/gzip.cpp)
+boost_iostreams_option(BOOST_IOSTREAMS_ENABLE_BZIP2 "Boost.Iostreams: Enable BZip2 support" BZip2 "" BZIP2_FOUND ${BOOST_IOSTREAMS_TARGET_BZIP2} src/bzip2.cpp)
+boost_iostreams_option(BOOST_IOSTREAMS_ENABLE_LZMA "Boost.Iostreams: Enable LZMA support" LibLZMA "" LIBLZMA_FOUND ${BOOST_IOSTREAMS_TARGET_LZMA} src/lzma.cpp)
+boost_iostreams_option(BOOST_IOSTREAMS_ENABLE_ZSTD "Boost.Iostreams: Enable Zstd support" zstd "1.0" zstd_FOUND ${BOOST_IOSTREAMS_TARGET_ZSTD} src/zstd.cpp)
 
 include(CheckCXXSourceCompiles)