Let eBPF ELF files be packaged in noarch packages

eBPF ELF represents a virtual machine where our file colors make no
sense at all. Filter out the color from these files to avoid a
"Arch dependent binaries in noarch package" error from them in noarch
packages.

We don't want to pull in clang to the check images just because of
this, so add a pre-built binary for the check and a simple way to
reproduce from the test-spec.

Fixes: #2875

build/rpmfc.c

@@ -1220,6 +1220,13 @@ static uint32_t getElfColor(const char *fn)
 		color = RPMFC_ELF32;
 		break;
 	    }
+
+	    /* Exceptions to coloring */
+	    switch (ehdr.e_machine) {
+	    case EM_BPF:
+		color = 0;
+		break;
+	    }
 	}
 	if (elf)
 	    elf_end(elf);

tests/data/SPECS/bpf.spec

@@ -0,0 +1,36 @@
+%bcond clang 0
+%define debug_package %{nil}
+
+Name: bpf
+Version: 1.0
+Release: 1
+Summary: Testing bpf ELF file behavior
+BuildArch: noarch
+License: GPL
+
+%description
+%{summary}
+
+%prep
+%setup -c -T
+
+%build
+%if %{with clang}
+cat << EOF > bpf.c
+int func(void)
+{
+    return 0;
+}
+EOF
+
+clang -target bpf -c bpf.c -o bpf.o
+%else
+cp /data/misc/bpf.o .
+%endif
+
+%install
+mkdir -p ${RPM_BUILD_ROOT}/opt/
+install -m755 bpf.o ${RPM_BUILD_ROOT}/opt/
+
+%files
+/opt/bpf.o

tests/rpmbuild.at

@@ -2766,3 +2766,15 @@ runroot rpmbuild --quiet -bb /data/SPECS/interact.spec
 [ignore],
 [ignore])
 RPMTEST_CLEANUP
+
+AT_SETUP([rpmbuild bpf file])
+AT_KEYWORDS([build])
+RPMDB_INIT
+
+RPMTEST_CHECK([
+runroot rpmbuild --quiet -bb /data/SPECS/bpf.spec
+],
+[0],
+[],
+[])
+RPMTEST_CLEANUP