Installed pkg-config files vary between Autotools and CMake

[arkadijs]

Describe the bug
portaudio-2.0.pc installed by Autotools and CMake builds vary, making predictable linking hard to attain.

Due to #918, an installation built with CMake is not functional because:

• only static library installed
• dependent libraries are not enumerated via pkg-config leading to linking errors.

User then must add platform-specific libs to link an application. Would shared library be also installed then it would just work, masking the issue. Developers who link statically know what to do but on average, as a developer, I'm presented with Undefined symbols error.

diff -u ./portaudio-2.0.pc.in ./cmake/portaudio-2.0.pc.in
--- ./portaudio-2.0.pc.in	2024-07-04 00:24:22
+++ ./cmake/portaudio-2.0.pc.in	2024-08-02 22:41:43
...
-Libs: -L${libdir} -lportaudio @LIBS@
-Cflags: -I${includedir} @THREAD_CFLAGS@
+Libs: -L${libdir} -lportaudio
+Libs.private: @PKGCONFIG_LDFLAGS_PRIVATE@
+Cflags: -I${includedir} @PKGCONFIG_CFLAGS@
+Requires.private: @PKGCONFIG_REQUIRES_PRIVATE@

sudo cmake --install build
-- Install configuration: "Release"
-- Installing: /usr/local/share/doc/PortAudio/portaudio/README.md
-- Installing: /usr/local/share/doc/PortAudio/portaudio/LICENSE.txt
-- Installing: /usr/local/lib/pkgconfig/portaudio-2.0.pc
-- Installing: /usr/local/lib/cmake/portaudio/PortAudioTargets.cmake
-- Installing: /usr/local/lib/cmake/portaudio/PortAudioTargets-release.cmake
-- Installing: /usr/local/lib/cmake/portaudio/PortAudioConfig.cmake
-- Installing: /usr/local/lib/cmake/portaudio/PortAudioConfigVersion.cmake
-- Installing: /usr/local/lib/libportaudio.a
-- Installing: /usr/local/include/portaudio.h
-- Installing: /usr/local/include/pa_mac_core.h

Autotools:

Libs: -L${libdir} -lportaudio -framework CoreAudio -framework AudioToolbox -framework AudioUnit -framework CoreFoundation -framework CoreServices
Cflags: -I${includedir} 

(missing -lm, BTW)

CMake:

cat /usr/local/lib/pkgconfig/portaudio-2.0.pc
...
Libs: -L${libdir} -lportaudio
Libs.private: -lm -framework CoreAudio -framework AudioToolbox -framework AudioUnit -framework CoreFoundation -framework CoreServices
Cflags: -I${includedir}
Requires.private: 

To Reproduce
Build with Autotools and attempt (static) link - it works.
Build with CMake - it doesn't, a lot of undefined symbols.

Expected behavior
If only static version is installed then linking against PortAudio must not require enumerating all dependent libraries - that should be handled via pkg-config.

Actual behavior

/opt/local/lib/go/pkg/tool/darwin_amd64/link: running /usr/bin/clang failed: exit status 1
Undefined symbols for architecture x86_64:
  "_AudioComponentFindNext", referenced from:
      _OpenAndSetupOneAudioUnit in libportaudio.a[15](pa_mac_core.c.o)
  "_AudioComponentInstanceDispose", referenced from:
      _CloseStream in libportaudio.a[15](pa_mac_core.c.o)
      _CloseStream in libportaudio.a[15](pa_mac_core.c.o)
      _OpenAndSetupOneAudioUnit in libportaudio.a[15](pa_mac_core.c.o)
  "_AudioComponentInstanceNew", referenced from:
      _OpenAndSetupOneAudioUnit in libportaudio.a[15](pa_mac_core.c.o)
...
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

(this is a Go app but the toolchain uses pkg-config internally)

Desktop:

• OS: any, in this case macOS
• PortAudio version: master HEAD

[RossBencina]

So #918 breaks the cmake install target?

But the earlier changes mean no static library is installed?

Am I correct to say that in our 19.7 release CMake built both static and dynamic libraries and installed them correctly? Whereas the current master builds only static or dynamic (not both), and does not install either correctly?