cmake: add support for static build

rt/CMakeLists.txt

@@ -1,6 +1,11 @@
 file(GLOB_RECURSE rt_sources *.c *.h include/ivy/rt/*.h)
 
-add_library(ivy-rt SHARED ${rt_sources})
+if (IVY_STATIC)
+	add_library(ivy-rt STATIC ${rt_sources})
+else ()
+	add_library(ivy-rt SHARED ${rt_sources})
+endif ()
+
 target_include_directories(ivy-rt PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include/)
 target_link_libraries(ivy-rt ivy-common)
-target_compile_definitions(ivy-rt PRIVATE IVY_EXPORT=1)
+target_compile_definitions(ivy-rt PRIVATE IVY_EXPORT=1 IVY_STATIC=${IVY_STATIC})