net: Relocate source files for consistency

src/net/CMakeLists.txt

@@ -2,7 +2,7 @@ set(src "src/common.c")
 
 if(PS1_BUILD)
     set(src ${src}
-        "src/ps1/net.c"
+        "ps1/src/net.c"
     )
 else()
     set(src ${src}
@@ -11,7 +11,7 @@ else()
     )
 
     if(WIN9X_BUILD OR ${CMAKE_HOST_SYSTEM_NAME} STREQUAL "Windows")
-        set(src ${src} "src/win9x/serial.c")
+        set(src ${src} "win9x/src/serial.c")
     else()
         # Assume POSIX if the command below executes successfully
         execute_process(COMMAND uname -m RESULT_VARIABLE result OUTPUT_QUIET)
@@ -19,7 +19,7 @@ else()
         if(result)
             message(FATAL_ERROR "Unknown operating system")
         else()
-            set(src ${src} "src/posix/serial.c")
+            set(src ${src} "posix/src/serial.c")
         endif()
     endif()