WIP: build static library of libmbus

libmbus_static_library.patch

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c47a94c..9230a64 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -95,8 +95,8 @@ set(PACKAGE_VERSION "${PROJECT_VERSION}")
 set(VERSION "${PROJECT_VERSION}")
 configure_file(${CMAKE_CURRENT_LIST_DIR}/mbus/config.h.in ${CMAKE_CURRENT_LIST_DIR}/config.h @ONLY)
 
-add_library(
-  ${PROJECT_NAME}
+# list of source files
+set(libsrc
   "${CMAKE_CURRENT_LIST_DIR}/mbus/mbus-protocol.c"
   "${CMAKE_CURRENT_LIST_DIR}/mbus/mbus-protocol.h"
   "${CMAKE_CURRENT_LIST_DIR}/mbus/mbus-tcp.c"
@@ -107,6 +107,16 @@ add_library(
   "${CMAKE_CURRENT_LIST_DIR}/mbus/mbus-protocol-aux.h"
   "${CMAKE_CURRENT_LIST_DIR}/mbus/mbus-serial.c"
   "${CMAKE_CURRENT_LIST_DIR}/mbus/mbus-serial.h")
+
+add_library(objlib OBJECT ${libsrc})
+
+# shared and static libraries built from the same object files
+add_library(${PROJECT_NAME} SHARED $<TARGET_OBJECTS:objlib>)
+add_library(libmbus_static STATIC $<TARGET_OBJECTS:objlib>)
+
+set_target_properties(${PROJECT_NAME} PROPERTIES PREFIX "")
+set_target_properties(libmbus_static PROPERTIES OUTPUT_NAME ${PROJECT_NAME})
+
 target_include_directories(
   ${PROJECT_NAME}
   PUBLIC "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}>" "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>"
@@ -118,8 +128,6 @@ if(NOT MSVC)
   target_compile_options(${PROJECT_NAME} PRIVATE -Wall -Wextra -Wno-pedantic)
 endif()
 
-set_target_properties(${PROJECT_NAME} PROPERTIES PREFIX "")
-
 if(CLANG_TIDY_EXE)
   set_target_properties(${PROJECT_NAME} PROPERTIES CXX_CLANG_TIDY "${CLANG_TIDY_EXE}")
 endif()