cmake: define BUILD_SHARED_LIBS option... in addition to be able to pass it on cmake invokation tools like ccmake et al. will show it as a configurable option
diff --git a/CMakeLists.txt b/CMakeLists.txt
index de68266..33e923e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,6 +14,11 @@ include(CMakePackageConfigHelpers)
include(sources.cmake)
#-----------------------------------------------------------------------------
+# Options
+#-----------------------------------------------------------------------------
+option(BUILD_SHARED_LIBS "Build shared library" FALSE)
+
+#-----------------------------------------------------------------------------
# library target
#-----------------------------------------------------------------------------
add_library(${PROJECT_NAME}