lipo availability [was: [PATCH v2] Makefile: link osxkeychain & support universal Rust]

[Ben Knoble <ben.knoble@gmail.com>]

> Le 2 juil. 2026 à 07:57, Patrick Steinhardt <ps@pks.im> a écrit :
> 
> On Wed, Jul 01, 2026 at 10:01:43PM +0000, Shardul Natu via GitGitGadget wrote:
>> From: Shnatu <snatu@google.com>
>> 
>> Also, introduce native support for macOS Universal Binaries
>> (multi-architecture builds) in the Git build system by allowing
>> the user to specify a list of target triples in the RUST_TARGETS
>> environment variable.
> 
>>  3. On macOS, if multiple targets are specified, we use lipo to
>>     combine them into a single Universal static library at
>>     target/release/libgitcore.a.
>> 
> 
>> diff --git a/Makefile b/Makefile
>> index 1f3f099f5c..8d49ecc897 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -3019,11 +3030,33 @@ scalar$X: scalar.o GIT-LDFLAGS $(GITLIBS)
>> $(LIB_FILE): $(LIB_OBJS)
>>    $(QUIET_AR)$(RM) $@ && $(AR) $(ARFLAGS) $@ $^
>> 
>> +ifndef NO_RUST
>> +ifeq ($(RUST_TARGETS),)
>> $(RUST_LIB): Cargo.toml $(RUST_SOURCES) $(LIB_FILE)
>>    $(QUIET_CARGO)cargo build $(CARGO_ARGS)
>> +else
>> +ifneq ($(words $(RUST_TARGETS)),1)
>> +ifneq ($(uname_S),Darwin)
>> +$(error Building universal Rust libraries requires macOS (lipo is not available on $(uname_S)))
>> +endif
>> +endif
>> +
>> +RUST_MEMBER_LIBS = $(foreach target,$(RUST_TARGETS),target/$(target)/$(RUST_BUILD_CONFIG)/$(RUST_LIB_NAME))
>> +$(RUST_MEMBER_LIBS): target/%/$(RUST_BUILD_CONFIG)/$(RUST_LIB_NAME): Cargo.toml $(RUST_SOURCES) $(LIB_FILE)
>> 
>> +    $(QUIET_CARGO)cargo build $(CARGO_ARGS) --target $*
>> +
>> +$(RUST_LIB): $(RUST_MEMBER_LIBS)
>> +    $(QUIET_GEN)\
>> +    if [ $(words $(RUST_TARGETS)) -gt 1 ]; then \
>> +        lipo -create $^ -output $@; \
> 
> Can we assume lipo to be generally available on macOS?

From my digging, universal binaries to support the PowerPC transition to Intel have been available since Xcode 2.1 from 2005 (whose release notes, if they ever existed, have been impossible for me to find). Of course for modern (Universal Binary 2) formats, you will need newer Xcode: the format was announced in 2020, so I suspect Xcode 12 is a minimum but not necessarily sufficient version. I have not been able to find a release note specific to UB2, though in 12.2 there is mention of both universal binaries and the arm architecture. Apple’s announcement [1] supports the argument for v12.

[1]: https://www.apple.com/au/newsroom/2020/06/apple-announces-mac-transition-to-apple-silicon/