http_client.c:39:18: error: idna.h: No such file or directory

cc skipfish.c -o skipfish -Wall -funsigned-char -g -ggdb -D_FORTIFY_SOURCE=0 -
I/usr/local/include/ -I/opt/local/include/ -O3 -Wno-format http_client.c database.c 
crawler.c analysis.c report.c -lcrypto -lssl -lidn -lz -L/usr/local/lib/ -
L/opt/local/lib
http_client.c:39:18: error: idna.h: No such file or directory
http_client.c: In function ‘parse_url’:
http_client.c:276: warning: implicit declaration of function ‘idna_to_ascii_8z’
http_client.c:276: error: ‘IDNA_SUCCESS’ undeclared (first use in this function)
http_client.c:276: error: (Each undeclared identifier is reported only once
http_client.c:276: error: for each function it appears in.)
make: *** [skipfish] Error 1

解決方法：
[root@local rpm-home]# yum install libidn-devel