Implement the HTTP plugin

Ended up including Joyent's http-parser library.

Makefile

@@ -5,6 +5,7 @@ CFLAGS = -std=c99 -Wall -Wextra -Wno-unused-function -ggdb
 # -lpthread is only there for debugging (gdb & errno)
 # -lrt is only for glibc < 2.17
 LDFLAGS = `pkg-config --libs libssl jansson` -lpthread -lrt -ldl -lcurses
+LDFLAGS_PLUGIN = $(LDFLAGS) -shared -fPIC
 
 .PHONY: all clean
 .SUFFIXES:
@@ -23,4 +24,8 @@ ponymap.1: ponymap
 	help2man -No $@ ./$<
 
 plugins/%.so: plugins/%.c utils.c plugin-api.h
-	$(CC) $< -o $@ $(CFLAGS) $(LDFLAGS) -shared -fPIC
+	$(CC) $< -o $@ $(CFLAGS) $(LDFLAGS_PLUGIN)
+
+plugins/http.so: plugins/http.c utils.c plugin-api.h \
+	http-parser/http_parser.c http-parser/http_parser.h
+	$(CC) $< http-parser/http_parser.c -o $@ $(CFLAGS) $(LDFLAGS_PLUGIN)