Provide rust-srpm-macros in RHEL

rust-srpm-macros is a dependency of redhat-rpm-config so that Rust-based
SRPMs can rely on these particular macros.  In RHEL 9 and earlier,
rust-srpm-macros was a separate source package which was included in
RHEL.  Since then, it became a subpackage of rust-packaging in Fedora.

In order to not pull in any part of rust-packaging into RHEL 10, thereby
allowing it to be maintained separately in EPEL, those macros are
provided here instead.

macros.rust-srpm

@@ -0,0 +1,62 @@
+# rust_arches: list of architectures where building Rust is supported
+#
+# Since RPM itself now depends on Rust code (via its GPG backend, rpm-sequoia),
+# this list will probably always be a superset of all architectures that are
+# supported by Fedora, which is why it is no longer required to set
+# "ExclusiveArch: rust_arches" for Rust packages in Fedora.
+%rust_arches x86_64 %{ix86} armv7hl aarch64 ppc64 ppc64le riscv64 s390x
+
+# version_no_tilde: lua macro for reconstructing the original crate version
+#       from the RPM version (i.e. replace any "~" characters with "-")
+%version_no_tilde() %{lua:
+    local sep = rpm.expand('%1')
+    local ver = rpm.expand('%2')
+\
+    if sep == '%1' then
+        sep = '-'
+    end
+\
+    if ver == '%2' then
+        ver = rpm.expand('%version')
+    end
+    ver = ver:gsub('~', sep)
+\
+    print(ver)
+}
+
+# __crates_url: default API endpoint for downloading .crate files from crates.io
+%__crates_url https://crates.io/api/v1/crates/
+
+# crates_source: lua macro for constructing the Source URL for a crate
+%crates_source() %{lua:
+    local crate = rpm.expand('%1')
+    local version = rpm.expand('%2')
+    local url = rpm.expand('%__crates_url')
+\
+    -- first argument missing: fall back to %crate
+    if crate == '%1' then
+        crate = rpm.expand('%crate')
+    end
+    -- %crate macro not defined: fall back to %name
+    if crate == '%crate' then
+        crate = rpm.expand('%name')
+    end
+\
+    -- second argument missing: fall back to %crate_version
+    if version == '%2' then
+        version = rpm.expand('%crate_version')
+    end
+    -- %crate_version macro not defined: fall back to %version
+    if version == '%crate_version' then
+        version = rpm.expand('%version')
+    end
+    -- replace '~' with '-' for backwards compatibility
+    -- can be removed in the future
+    version = version:gsub('~', '-')
+\
+    print(url .. crate .. '/' .. version .. '/download#/' .. crate .. '-' .. version .. '.crate')
+}
+
+# __cargo_skip_build: unused macro, set to 0 for backwards compatibility
+%__cargo_skip_build 0
+

rust.spec

@@ -125,6 +125,7 @@ Patch6:         0001-bootstrap-only-show-PGO-warnings-when-verbose.patch
 
 # Simple rpm macros for rust-toolset (as opposed to full rust-packaging)
 Source100:      macros.rust-toolset
+Source101:      macros.rust-srpm
 
 # Disable cargo->libgit2->libssh2 on RHEL, as it's not approved for FIPS (rhbz1732949)
 Patch100:       rustc-1.75.0-disable-libssh2.patch
@@ -520,6 +521,14 @@ useful as a reference for code completion tools in various editors.
 
 %if 0%{?rhel}
 
+%package srpm-macros
+Summary:        RPM macros for building Rust source packages
+BuildArch:      noarch
+
+%description srpm-macros
+RPM macros for building source packages for Rust projects.
+
+
 %package toolset
 Summary:        Rust Toolset
 BuildArch:      noarch
@@ -848,6 +857,7 @@ rm -f %{buildroot}%{rustlibdir}/%{rust_triple}/bin/rust-ll*
 %if 0%{?rhel}
 # This allows users to build packages using Rust Toolset.
 %{__install} -D -m 644 %{S:100} %{buildroot}%{rpmmacrodir}/macros.rust-toolset
+%{__install} -D -m 644 %{S:101} %{buildroot}%{rpmmacrodir}/macros.rust-srpm
 %endif
 
 
@@ -1027,6 +1037,9 @@ rm -rf "./build/%{rust_triple}/stage2-tools/%{rust_triple}/cit/"
 
 
 %if 0%{?rhel}
+%files srpm-macros
+%{rpmmacrodir}/macros.rust-srpm
+
 %files toolset
 %{rpmmacrodir}/macros.rust-toolset
 %endif