Fix Windows build: Remove rubberband due to static linking incompatibility

[Copilot]

Windows builds were failing with 7 unresolved external symbols when linking the Python extension. Root cause analysis revealed that vcpkg's rubberband package on Windows is fundamentally incompatible with static linking - it expects SLEEF libraries as DLLs (indicated by __imp_ symbol prefixes) rather than static libraries.

Solution

Removed rubberband and SLEEF from Windows builds in vcpkg.json by changing platform filter from "!linux" to "osx". Windows will use dummy timestretch/pitchshift implementations instead.

Changes

vcpkg.json

• Updated rubberband platform filter: "!linux" → "osx" (macOS only)
• Updated sleef platform filter: "!linux" → "osx" (macOS only)

python/meson.build

• Fixed bug where platform-specific system libraries were incorrectly added to dependencies variable (for C library) instead of pyaubio_deps (for Python extension)
• Introduced pyaubio_extra_deps to properly collect platform-specific system libraries
• Windows: ws2_32, secur32, bcrypt, mfuuid, strmiids, ole32 (required by FFmpeg's networking, security, and Media Foundation components)
• Linux: pthread and libstdc++ (required for FFmpeg)
• Fixed dependency chain: pyaubio_deps = [py.dependency(), libaubio_static_dep] + pyaubio_extra_deps

Impact

• ✅ Windows builds succeed
• ❌ Windows loses rubberband time-stretch/pitch-shift features (uses dummy implementations)
• ✅ Core aubio functionality (onset, pitch, tempo, MFCC) unchanged
• ✅ macOS retains full rubberband support
• ✅ Linux unaffected (already didn't have rubberband)

Root Cause

vcpkg's rubberband package on Windows builds with DLL import expectations for SLEEF libraries. The __imp_ symbol prefix indicates rubberband.lib was built expecting SLEEF as a DLL, not a static library. This is a vcpkg packaging limitation that prevents true static linking on Windows.

Error Example (Before Fix)

rubberband.lib(src_common_FFT.cpp.obj) : error LNK2019: unresolved external symbol __imp_Sleef_malloc
rubberband.lib(src_common_FFT.cpp.obj) : error LNK2019: unresolved external symbol __imp_SleefDFT_double_init1d
rubberband.lib(src_common_FFT.cpp.obj) : error LNK2019: unresolved external symbol __imp_SleefDFT_float_execute
avformat.lib(network.o) : error LNK2019: unresolved external symbol __imp_WSAStartup
avutil.lib(random_seed.o) : error LNK2019: unresolved external symbol BCryptGenRandom

Documentation

See WINDOWS_RUBBERBAND_REMOVAL.md and WINDOWS_BUILD_FIX_SUMMARY.md for comprehensive technical details and rationale.

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[shauneccles]

@copilot Carefully review the most recent run and resolve the issues that caused the build failure.

Pay attention to the root cause and resolve it rather than working around it.

If the root cause is a true inability to statically link rubberband then identify why and remove rubberband from the CI build.

[shauneccles]

@copilot Review the changes made in previous commits to try to fix the rubberband issue and remove any changes that are no longer required since we are not building rubberband

[Copilot]

@copilot Review the changes made in previous commits to try to fix the rubberband issue and remove any changes that are no longer required since we are not building rubberband

Reviewed and cleaned up in commit 66d4123.

Removed:

• SLEEF DFT library detection from meson.build (lines 499-510) - This was added specifically to fix Windows rubberband linking and is no longer needed.

Kept:

• python/meson.build changes - These fix a bug where platform-specific libraries were incorrectly added to the dependencies variable (for C library) instead of pyaubio_deps (for Python extension). The Windows system libraries (ws2_32, secur32, bcrypt, mfuuid, strmiids, ole32) are still required for FFmpeg static linking, not rubberband.