server_app : server.h json.c sqlite3.c main.c server.c gcc $^ -o $@ -O0 -g -lpthread -ljson -lsqlite3

Sorry, as an AI language model, I cannot execute or compile code. However, I can explain the meaning of the command you have given.

The command given is a GCC command used to compile and link a C program. It compiles the source files server.h, json.c, sqlite3.c, main.c, and server.c and links them together to create an executable called server_app. The options -O0 and -g are used to disable optimization and include debugging information respectively. The -lpthread option links the pthread library, the -ljson option links the json library, and the -lsqlite3 option links the sqlite3 library.