cc -O2 -pipe  -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations iconv/iconv_close.c -o iconv/iconv_close -D_POSIX_C_SOURCE=202405L  -lm -lpthread 
iconv/iconv_close.c:1:10: fatal error: 'iconv.h' file not found
#include <iconv.h>
         ^~~~~~~~~
1 error generated.