Suricata

https://buildbot.suricata-ids.org/builders/pcap%20openbsd-5.2/builds/131/steps/shell_5/logs/stdio

checking iconv.h usability... yes
checking iconv.h presence... yes
checking for iconv.h... yes
checking for libiconv_close in -liconv... yes

/bin/sh ../libtool --tag=CC    --mode=compile gcc -DHAVE_CONFIG_H -I. -I.. -I..   -O2 -D_GNU_SOURCE -g -Wall -Wextra -std=gnu99 -pedantic  -Wextra -Wno-missing-field-initializers -Wshadow -Wpointer-arith  -Wstrict-prototypes -Wmissing-prototypes -Wno-unused-parameter -O2 -Wstrict-overflow=1 -fstack-protector -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security -MT htp_config.lo -MD -MP -MF .deps/htp_config.Tpo -c -o htp_config.lo htp_config.c
libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I.. -I.. -O2 -D_GNU_SOURCE -g -Wall -Wextra -std=gnu99 -pedantic -Wextra -Wno-missing-field-initializers -Wshadow -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wno-unused-parameter -O2 -Wstrict-overflow=1 -fstack-protector -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security -MT htp_config.lo -MD -MP -MF .deps/htp_config.Tpo -c htp_config.c  -fPIC -DPIC -o .libs/htp_config.o
In file included from htp_config.c:39:
htp_private.h:54:19: error: iconv.h: No such file or directory

Odd that it appears that iconv.h does exist, but libhtp doesn't find it.