Built-tested with clang and GCC on FreeBSD 15.0/amd64.
```
$ cat > test.pc << EOF
Name: test
Version: 1.0
Description: Just a test
EOF
$ PKG_CONFIG_PATH=`pwd` bomtool test | head
SPDXVersion: SPDX-2.2
DataLicense: CC0-1.0
SPDXID: SPDXRef-DOCUMENT
DocumentName: SBOM-SPDX-testC401.0
DocumentNamespace: https://spdx.org/spdxdocs/bomtool
Creator: Tool: bomtool
Created: 2026-06-30T18:36:20Z
##### Package: test@1.0
$ PKG_CONFIG_PATH=`pwd` spdxtool test | head
{
"@context": "https://spdx.org/rdf/3.0.1/spdx-context.jsonld",
"@graph": [
{
"type": "Agent",
"creationInfo": "_:creationinfo_1",
"spdxId": "https://github.com/pkgconf/pkgconf/Agent/default",
"name": "Default"
},
{
$ pkg-config --cflags --libs panelw
-fstack-protector-strong -lpanelw
```