Add a test that does some basic validation of the pkg-config files.
Example run:
./tests/scripts/all.sh test_cmake_as_package
<snip>
******************************************************************
* test_cmake_as_package: build: cmake 'as-package' build
* Wed Sep 11 16:17:41 UTC 2024
******************************************************************
cmake .
make
Built against Mbed TLS 3.6.0
testing package config file: mbedtls ... passed
testing package config file: mbedx509 ... passed
testing package config file: mbedcrypto ... passed
make clean
Signed-off-by: Bill Roberts <bill.roberts@arm.com>
