how to add boost via -I flag to meson.build

Question

Introduction:

The main objective is having the ability to debug c++ code with F5 (Run->start debugging) in vs code via meson/ninja build system.

This can be done by following stenosis's answer here. Unfortunately, this feature has broken when I added boost library to the project. The program won't compile via F5, because vs code running meson as a task can't find the boost library:

meson.build:33:0: ERROR: Dependency "boost" not found, tried system

(Note that meson compile works, because I defined export BOOST_ROOT=/usr/local/boost_1_78_0/).

Question

I have a feeling that the solution is to add /usr/local/boost_1_78_0/ to search directory (-I flag) in meson.build file. How can one specify this?

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Notes and tried approaches:

1. I added -I and /usr/local/boost_1_78_0/ as arguments to tasks.json according to this question (I include only boost headers in my project), but then I get:

> Executing task: 'meson build --buildtype=debug && cd builddir && ninja' -I /usr/local/boost_1_78_0/ <

/usr/bin/bash: meson build --buildtype=debug && cd builddir && ninja: command not found

2. I typed meson configure -Dpkg_config_path=/usr/local/boost_1_78_0/ but this didn't work.

3. Meson documentation specifies setting the custom path to the library in native files, but I didn't work it out thoroughly. At a first glance, it looks like overcomplicated approach to a simple problem.

4. (slightly tangent) Debuging with F5 in vs code can also be triggered by specifying backend_startup_project in Meson build.file. This worked for me on former version of Meson (0.58.?), but now (v. 0.60.3) I come across this bug and I must comment out this fragment or I get meson.build:4:25: ERROR: Expecting rparen got id.

EDIT:

• I add boost as the dependency in the following way:

boost_dep = dependency('boost')

executable('main', 'main.cpp', sources : sourcelist, dependencies : [..., boost_dep])