aql: configure header for standard library files location

Let's start working on a standard library [1]. The idea is that we
bundle some aql files with predefined functions (and procedures) and we
load them when aql prompt starts.

So let's prepare a configuration file with a location for the scripts.
The location is currently only in local dev tree. We will later change
that to some /usr/share or /usr/lib location.

[1] #221

aql2/CMakeLists.txt

@@ -29,3 +29,11 @@ if(FETCH_NEW_TCLAP)
 	target_include_directories(aql2 SYSTEM PUBLIC ${CMAKE_BINARY_DIR}/tclap-src/include/) # There are many warnings inside tclap, use -isystem instead of -I
 endif()
 # hack end
+
+# stdlib
+set(STDLIB_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/src/stdlib")
+configure_file(
+	${CMAKE_CURRENT_SOURCE_DIR}/src/aql.h.in
+	${CMAKE_CURRENT_BINARY_DIR}/aql.h
+	)
+set(CMAKE_INCLUDE_CURRENT_DIR ON)

aql2/src/aql.h.in

+#pragma once
+
+#define STDLIB_DIRECTORY "@STDLIB_DIRECTORY@"
+