Can't solve the issue of "you just don't have the library (or a specific version thereof) installed".
But you can make it worse by changing "You must have version X of library Y installed" to "You must have version X of library Y compiled by compiler Z installed".
As-is, one can reasonably achieve ABI stability for their C library if they want to; really all it takes is "don't modify exposed types or signatures of exposed functions" and "don't use intmax_t", and currently you can actually break the latter.
Release vs debug shouldn't affect ABI (or, at least, the library author can decide whether it does; all it takes is.. not having `#if DEBUG` in your exposed header files changing types or function signatures).
Multi-threading doesn't affect ABI in any way at all.
fast-math doesn't affect ABI (maybe you mean the setting of FTZ/DAZ? but modern clang & gcc don't do that either, and anyway that breaks everything float in general, ABI itself is one of the few float things that don't immediately break, really).
Presence or absence of SIMD extensions, hard-float, or indeed any other form of extension, also doesn't modify the ABI by itself.
There's a separate -mabi=... that controls hard-float & co, but generally people don't touch that, and those that do, well, have a clear indication of "abi" in "-mabi" that tells them that they're touching something about ABI. (SIMD does have some asterisks on passing around SIMD types, but gcc does give a -Wpsabi warning when using a natively-unsupported SIMD type in a function signature; and this affects only very specialized low-level libraries, and said functions should be marked via an attribute to assume the presence of the necessary intended extension anyway, and probably are header-only and thus unaffected in the first place)
That said, it would probably make sense to have a way to configure -mabi at the function level (if this doesn't already exist).
General CPU ISA is one thing that does inescapably affect ABI of compiled programs; but you can have a stable ABI within one ISA. But yes, there's the wider requirement of "You must have version X of library Y for ISA W installed", but yet "You must have version X of library Y for ISA W compiled by compiler Z installed" is still worse.
Can't solve the issue of "you just don't have the library (or a specific version thereof) installed".
But you can make it worse by changing "You must have version X of library Y installed" to "You must have version X of library Y compiled by compiler Z installed".
As-is, one can reasonably achieve ABI stability for their C library if they want to; really all it takes is "don't modify exposed types or signatures of exposed functions" and "don't use intmax_t", and currently you can actually break the latter.
You forgot about binaries compiled with incompatible build or linker flags.
There is a reason why commercial software has several combinations on their SDKs, for their libraries.
Release, debug, multi-threaded, with math emulation, with fast math, specific CPU ISA with and without SIMD, and these are only the most common ones.
Release vs debug shouldn't affect ABI (or, at least, the library author can decide whether it does; all it takes is.. not having `#if DEBUG` in your exposed header files changing types or function signatures).
Multi-threading doesn't affect ABI in any way at all.
fast-math doesn't affect ABI (maybe you mean the setting of FTZ/DAZ? but modern clang & gcc don't do that either, and anyway that breaks everything float in general, ABI itself is one of the few float things that don't immediately break, really).
Presence or absence of SIMD extensions, hard-float, or indeed any other form of extension, also doesn't modify the ABI by itself.
There's a separate -mabi=... that controls hard-float & co, but generally people don't touch that, and those that do, well, have a clear indication of "abi" in "-mabi" that tells them that they're touching something about ABI. (SIMD does have some asterisks on passing around SIMD types, but gcc does give a -Wpsabi warning when using a natively-unsupported SIMD type in a function signature; and this affects only very specialized low-level libraries, and said functions should be marked via an attribute to assume the presence of the necessary intended extension anyway, and probably are header-only and thus unaffected in the first place)
That said, it would probably make sense to have a way to configure -mabi at the function level (if this doesn't already exist).
General CPU ISA is one thing that does inescapably affect ABI of compiled programs; but you can have a stable ABI within one ISA. But yes, there's the wider requirement of "You must have version X of library Y for ISA W installed", but yet "You must have version X of library Y for ISA W compiled by compiler Z installed" is still worse.
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