finalize SASL, move all IRC-related includes to a specific folder

Makefile

@@ -1,14 +1,15 @@
-CC := clang
-CFLAGS := -I include -Wall -Wextra
-CFLAGS_DBG := $(CFLAGS) -g -O0
-CFLAGS_REL := $(CFLAGS) -O2
-
-LDFLAGS := 
-LDFLAGS_REL := $(LDFLAGS) -s
-
 BUILD_DIR := build
 SRC_DIR := src
 INCLUDE_DIR := include
+PRIVATE_INCLUDE_DIR := privinclude
+
+CC := clang
+CFLAGS := -I $(INCLUDE_DIR) -I $(PRIVATE_INCLUDE_DIR) -Wall -Wextra
+CFLAGS_DBG := $(CFLAGS) -g -O0
+CFLAGS_REL := $(CFLAGS) -O2
+
+LDFLAGS :=
+LDFLAGS_REL := $(LDFLAGS) -s
 
 APPLICATION := bbirc
 APPLICATION_DBG := bbirc-debug