meson: Exploit file.full_path() for config.h

We hit some hazards previously with include-ordering when libpldm
was built as a meson subproject. Specifying the full path avoids the
problem.

Fix the current implementation, which causes the following output:

```
WARNING: Broken features used:
 * 1.3.0: {'str.format: Value other than strings, integers, bools, options, dictionaries and lists thereof.'}
```

Using file.full_path() requires we bump the minimum meson version to
1.4.0.

Change-Id: I4326ef40a811c0d9df229683e7d79833424e5c6d
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
diff --git a/meson.build b/meson.build
index 4cab166..aab10c9 100644
--- a/meson.build
+++ b/meson.build
@@ -12,7 +12,7 @@
         'tests': not meson.is_subproject(),
     },
     version: '0.11.0',
-    meson_version: '>=1.3.0',
+    meson_version: '>=1.4.0',
 )
 
 if get_option('tests')
@@ -67,7 +67,7 @@
 
 config = configure_file(output: 'config.h', configuration: conf)
 
-add_project_arguments('-include', '@0@'.format(config), language: 'c')
+add_project_arguments('-include', config.full_path(), language: 'c')
 
 libpldm_include_dir = include_directories('include', is_system: true)