diff --git a/gnu/packages/zig.scm b/gnu/packages/zig.scm
index bc3e1c019a..08ee650d8b 100644
--- a/gnu/packages/zig.scm
+++ b/gnu/packages/zig.scm
@@ -30,10 +30,10 @@ (define-module (gnu packages zig)
   #:use-module (gnu packages compression)
   #:use-module (gnu packages llvm))
 
-(define-public zig-0.10
+(define-public zig-0.9
   (package
     (name "zig")
-    (version "0.10.1")
+    (version "0.9.1")
     (source
      (origin
        (method git-fetch)
@@ -42,57 +42,66 @@ (define-public zig-0.10
              (commit version)))
        (file-name (git-file-name name version))
        (sha256
-        (base32 "1sh5xjsksl52i4cfv1qj36sz5h0ln7cq4pdhgs3960mk8a90im7b"))
-       (patches (search-patches "zig-do-not-link-against-librt.patch"))))
+        (base32 "0nfvgg23sw50ksy0z0ml6lkdsvmd0278mq29m23dbb2jsirkhry7"))
+       (patches (search-patches "zig-0.9-riscv-support.patch"
+                                "zig-use-system-paths.patch"
+                                "zig-do-not-link-against-librt.patch"))))
     (build-system cmake-build-system)
-    (inputs
-     (list clang-15 ; Clang propagates llvm.
-           lld-15
-           zlib
-           (list zstd "lib")))
-    ;; Zig compiles fine with GCC, but also needs native LLVM libraries.
-    (native-inputs
-     (list llvm-15))
     (arguments
      (list
       #:configure-flags
       #~(list #$@(if (%current-target-system)
                      (list (string-append "-DZIG_TARGET_TRIPLE="
                                           (%current-target-system)))
-                     '())
-              "-DZIG_TARGET_MCPU=baseline"
-              "-DZIG_SHARED_LLVM=ON"
-              (string-append "-DZIG_LIB_DIR=" #$output "/lib/zig"))
-      #:validate-runpath? #f            ;TODO: zig binary can't find ld-linux.
-      #:out-of-source? #f               ;for tests
+                     '()))
+      #:out-of-source? #f         ; for tests
+      ;; There are too many unclear test failures.
+      #:tests? (not (or (target-riscv64?)
+                        (%current-target-system)))
       #:phases
       #~(modify-phases %standard-phases
-          (add-after 'unpack 'set-env-variables
+          #$@(if (target-riscv64?)
+                 ;; It is unclear why all these tests fail to build.
+                 `((add-after 'unpack 'adjust-tests
+                     (lambda _
+                       (substitute* "build.zig"
+                         ((".*addRuntimeSafetyTests.*") "")
+                         ((".*addRunTranslatedCTests.*") ""))
+                       (substitute* "test/standalone.zig"
+                         ;; These tests fail to build on riscv64-linux.
+                         ;; They both contain 'exe.linkSystemLibrary("c");'
+                         ((".*shared_library.*") "")
+                         ((".*mix_o_files.*") "")
+                         ;; ld.lld: error: undefined symbol: __tls_get_addr
+                         ;; Is this symbol x86 only in glibc?
+                         ((".*link_static_lib_as_system_lib.*") "")))))
+                 '())
+          (add-after 'configure 'set-cache-dir
             (lambda _
-              ;; Set CC, since the stage 2 zig relies on it to find the libc
-              ;; installation, and otherwise silently links against its own.
-              (setenv "CC" #$(cc-for-target))
               ;; Set cache dir, otherwise Zig looks for `$HOME/.cache'.
               (setenv "ZIG_GLOBAL_CACHE_DIR"
                       (string-append (getcwd) "/zig-cache"))))
-          (add-after 'patch-source-shebangs 'patch-more-shebangs
-            (lambda* (#:key inputs #:allow-other-keys)
-              ;; Zig uses information about /usr/bin/env to determine the
-              ;; version of glibc and other data.
-              (substitute* "lib/std/zig/system/NativeTargetInfo.zig"
-                (("/usr/bin/env") (search-input-file inputs "/bin/env")))))
           (delete 'check)
           (add-after 'install 'check
             (lambda* (#:key tests? #:allow-other-keys)
               (when tests?
                 (invoke (string-append #$output "/bin/zig")
-                        "build" "test"
-                        ;; We're not testing the compiler bootstrap chain.
-                        "-Dskip-stage1"
+                        ;; Testing the standard library takes >7.5GB RAM, and
+                        ;; will fail if it is OOM-killed.  The 'test-toolchain'
+                        ;; target skips standard library and doc tests.
+                        "build" "test-toolchain"
+                        ;; Stage 2 is experimental, not what we run with `zig',
+
                         "-Dskip-stage2-tests"
                         ;; Non-native tests try to link and execute non-native
                         ;; binaries.
                         "-Dskip-non-native")))))))
+    (inputs
+     (list clang-13                     ;Clang propagates llvm.
+           lld-13))
+    ;; Zig compiles fine with GCC, but also needs native LLVM libraries.
+    (native-inputs
+     (list llvm-13))
     (native-search-paths
      (list
       (search-path-specification
@@ -123,11 +132,11 @@ (define-public zig-0.10
     (properties `((max-silent-time . 9600)))
     (license license:expat)))
 
-(define-public zig-0.9
+(define-public zig-0.10
   (package
-    (inherit zig-0.10)
+    (inherit zig-0.9)
     (name "zig")
-    (version "0.9.1")
+    (version "0.10.1")
     (source
      (origin
        (method git-fetch)
@@ -136,64 +145,52 @@ (define-public zig-0.9
              (commit version)))
        (file-name (git-file-name name version))
        (sha256
-        (base32 "0nfvgg23sw50ksy0z0ml6lkdsvmd0278mq29m23dbb2jsirkhry7"))
-       (patches (search-patches "zig-0.9-riscv-support.patch"
-                                "zig-use-system-paths.patch"
-                                "zig-do-not-link-against-librt.patch"))))
+        (base32 "1sh5xjsksl52i4cfv1qj36sz5h0ln7cq4pdhgs3960mk8a90im7b"))
+       (patches (search-patches "zig-do-not-link-against-librt.patch"))))
+    (arguments
+     (substitute-keyword-arguments (package-arguments zig-0.9)
+       ((#:configure-flags flags ''())
+        #~(cons* "-DZIG_TARGET_MCPU=baseline"
+                 "-DZIG_SHARED_LLVM=ON"
+                 (string-append "-DZIG_LIB_DIR=" #$output "/lib/zig")
+                 #$flags))
+       ;; TODO: zig binary can't find ld-linux.
+       ((#:validate-runpath? _ #t) #f)
+       ((#:tests? _ #t) #t)
+       ((#:phases phases '%standard-phases)
+        #~(modify-phases #$phases
+            #$@(if (target-riscv64?)
+                   `((delete 'adjust-tests))
+                   '())
+            (add-after 'unpack 'set-CC
+              (lambda _
+                ;; Set CC, since the stage 2 zig relies on it to find the libc
+                ;; installation, and otherwise silently links against its own.
+                (setenv "CC" #$(cc-for-target))))
+            (add-after 'patch-source-shebangs 'patch-more-shebangs
+              (lambda* (#:key inputs #:allow-other-keys)
+                ;; Zig uses information about /usr/bin/env to determine the
+                ;; version of glibc and other data.
+                (substitute* "lib/std/zig/system/NativeTargetInfo.zig"
+                  (("/usr/bin/env") (search-input-file inputs "/bin/env")))))
+            (replace 'check
+              (lambda* (#:key tests? #:allow-other-keys)
+                (when tests?
+                  (invoke (string-append #$output "/bin/zig")
+                          "build" "test"
+                          ;; We're not testing the compiler bootstrap chain.
+                          "-Dskip-stage1"
+                          "-Dskip-stage2-tests"
+                          ;; Non-native tests try to link and execute non-native
+                          ;; binaries.
+                          "-Dskip-non-native"))))))))
     (inputs
-     (list clang-13 ; Clang propagates llvm.
-           lld-13))
-    ;; Zig compiles fine with GCC, but also needs native LLVM libraries.
+     (modify-inputs (package-inputs zig-0.9)
+       (prepend zlib `(,zstd "lib"))
+       (replace "clang" clang-15)
+       (replace "lld" lld-15)))
     (native-inputs
-     (list llvm-13))
-    (arguments
-     (list
-      #:configure-flags
-      #~(list #$@(if (%current-target-system)
-                     (list (string-append "-DZIG_TARGET_TRIPLE="
-                                          (%current-target-system)))
-                     '()))
-      #:out-of-source? #f         ; for tests
-      ;; There are too many unclear test failures.
-      #:tests? (not (or (target-riscv64?)
-                        (%current-target-system)))
-      #:phases
-      #~(modify-phases %standard-phases
-          (add-after 'configure 'set-cache-dir
-            (lambda _
-              ;; Set cache dir, otherwise Zig looks for `$HOME/.cache'.
-              (setenv "ZIG_GLOBAL_CACHE_DIR"
-                      (string-append (getcwd) "/zig-cache"))))
-          #$@(if (target-riscv64?)
-                 ;; It is unclear why all these tests fail to build.
-                 `((add-after 'unpack 'adjust-tests
-                     (lambda _
-                       (substitute* "build.zig"
-                         ((".*addRuntimeSafetyTests.*") "")
-                         ((".*addRunTranslatedCTests.*") ""))
-                       (substitute* "test/standalone.zig"
-                         ;; These tests fail to build on riscv64-linux.
-                         ;; They both contain 'exe.linkSystemLibrary("c");'
-                         ((".*shared_library.*") "")
-                         ((".*mix_o_files.*") "")
-                         ;; ld.lld: error: undefined symbol: __tls_get_addr
-                         ;; Is this symbol x86 only in glibc?
-                         ((".*link_static_lib_as_system_lib.*") "")))))
-                 '())
-          (delete 'check)
-          (add-after 'install 'check
-            (lambda* (#:key tests? #:allow-other-keys)
-              (when tests?
-                (invoke (string-append #$output "/bin/zig")
-                        ;; Testing the standard library takes >7.5GB RAM, and
-                        ;; will fail if it is OOM-killed.  The 'test-toolchain'
-                        ;; target skips standard library and doc tests.
-                        "build" "test-toolchain"
-                        ;; Stage 2 is experimental, not what we run with `zig',
-
-                        "-Dskip-stage2-tests"
-                        ;; Non-native tests try to link and execute non-native
-                        ;; binaries.
-                        "-Dskip-non-native")))))))))
+     (modify-inputs (package-native-inputs zig-0.9)
+       (replace "llvm" llvm-15)))))
 
 (define-public zig zig-0.10)
