rpmrc: Add architecture compatibility mapping between aarch64 and arm64

AArch64 has another common name for the architecture: arm64. And while compilers,
the kernel, and RPM use "aarch64", a number of language ecosystems use "arm64".

In addition, Debian packages use the "arm64" architecture name to refer to "aarch64",
and AArch64 packages that are translated from DEB to RPM format tend to not be
installable because there's not a sufficient architecture mapping.

This change adds the "arm64" identifier as an alias for "aarch64" so that this works
as expected, rather than breaking on unknown architectures.

rpmrc.in

@@ -99,6 +99,7 @@ optflags: sh4 -O2 -g -mieee
 optflags: sh4a -O2 -g -mieee
 
 optflags: aarch64 -O2 -g
+optflags: arm64 -O2 -g
 
 optflags: riscv64 -O2 -g
 
@@ -242,7 +243,9 @@ arch_canon:	sh3: sh3	17
 arch_canon:	sh4: sh4	17
 arch_canon:	sh4a: sh4a	17
 arch_canon:	xtensa: xtensa	18
-arch_canon:	aarch64: aarch64 19
+
+arch_canon:	aarch64: aarch64	19
+arch_canon:	arm64: arm64		19
 
 arch_canon:	mipsr6: mipsr6	20
 arch_canon:	mipsr6el: mipsr6el	20
@@ -377,6 +380,7 @@ buildarchtranslate: sh4: sh4
 buildarchtranslate: sh4a: sh4
 
 buildarchtranslate: aarch64: aarch64
+buildarchtranslate: arm64: aarch64
 
 buildarchtranslate: riscv: riscv64
 buildarchtranslate: riscv64: riscv64
@@ -485,7 +489,8 @@ arch_compat: sh3: noarch
 arch_compat: sh4: noarch
 arch_compat: sh4a: sh4
 
-arch_compat: aarch64: noarch
+arch_compat: aarch64: arm64 noarch
+arch_compat: arm64: aarch64 noarch
 
 arch_compat: riscv: noarch
 arch_compat: riscv64: noarch
@@ -522,6 +527,7 @@ os_compat: Darwin: MacOSX
 buildarch_compat: ia64: noarch
 
 buildarch_compat: aarch64: noarch
+buildarch_compat: arm64: aarch64
 
 buildarch_compat: riscv: noarch
 buildarch_compat: riscv64: noarch