Convert EMSCRIPTEN build target to an OBJECT library

Previously, the EMSCRIPTEN build target was an executable, which is not ideal for modular code reuse. Changing it to an OBJECT library facilitates better modularization and allows for more flexibility in linking with other targets. This update preserves existing library settings and options.

CMakeLists.txt

@@ -12,14 +12,7 @@ set(OasisC_SOURCES
         src/Divide.cpp)
 
 if (DEFINED EMSCRIPTEN)
-    add_executable(OasisC ${OasisC_SOURCES})
-    target_link_libraries(OasisC PUBLIC embind)
-    target_link_options(OasisC PUBLIC
-            --no-entry
-            "-sSINGLE_FILE"
-            "-sEXPORTED_RUNTIME_METHODS=ccall,cwrap"
-            "-sENVIRONMENT='web'"
-            "--emit-tsd OasisC.d.ts")
+    add_library(OasisC OBJECT ${OasisC_SOURCES})
 else ()
     add_library(OasisC ${OasisC_SOURCES})
 endif ()