ci/test: source cmocka via meson wrap so srp_unit_test always builds

srp_unit_test had been silently skipping in test-ubuntu because the
runner image (libplacebo-ubuntu-jammy) ships without libcmocka-dev
and does not give the CI user write access to /var/lib/apt/lists, so
an in-script apt-get install cannot fix it.  The silent skip is how
the SRP fixture drift reported in #215 reached a release tag.

Switch the meson detection from cc.find_library('cmocka', required:
false) to dependency('cmocka', required: false, fallback:
['cmocka', 'cmocka_dep']) and add subprojects/cmocka.wrap pointing
at WrapDB cmocka_1.1.8-1.  When the runner image has cmocka the
system copy is used; otherwise meson builds it as a subproject.
Existing .gitignore rules (/subprojects/* with !*.wrap) keep the
fetched source out of the tree.

srp_unit's link line now picks up bcrypt on Windows because
random.c calls BCryptGenRandom; the main librist target was already
pulling it in via the top-level deps list, but srp_unit links
random.c directly.

Drop the broken apt-get line from the test-ubuntu script and add
retry: 2 to both test jobs to absorb the simple+multicast environmental
flake that surfaces on the shared runner regardless of branch.

.gitlab-ci.yml

@@ -64,7 +64,13 @@ test-ubuntu:
     extends:
         - .ubuntu-amd64-jammy
     needs: ["build-ubuntu"]
+    # simple+multicast cases are environmentally flaky on the shared
+    # runner (UDP/IGMP timing); retry covers transient failures.
+    retry: 2
     script:
+        # cmocka comes from subprojects/cmocka.wrap when the runner image
+        # does not ship libcmocka-dev; #215 used to slip silently because
+        # the meson check skipped srp_unit_test entirely.
         - meson build --buildtype release -Db_sanitize=address,undefined
         - cd build && meson test --print-errorlogs
     dependencies:
@@ -98,6 +104,7 @@ test-win64:
     extends: .debian-amd64-common
     needs: ["build-win64"]
     allow_failure: true
+    retry: 2
     dependencies:
         - build-win64
     script:

subprojects/cmocka.wrap

@@ -0,0 +1,13 @@
+[wrap-file]
+directory = cmocka-1.1.8
+source_url = https://cmocka.org/files/1.1/cmocka-1.1.8.tar.xz
+source_filename = cmocka-1.1.8.tar.xz
+source_hash = 58435b558766d7f4c729ba163bdf3aec38bed3bc766dab684e3526ed0aa7c780
+patch_filename = cmocka_1.1.8-1_patch.zip
+patch_url = https://wrapdb.mesonbuild.com/v2/cmocka_1.1.8-1/get_patch
+patch_hash = ed475edc7c511d531bf0b14e6743d124f048eb00225c52fce2a8f196bd29a345
+source_fallback_url = https://github.com/mesonbuild/wrapdb/releases/download/cmocka_1.1.8-1/cmocka-1.1.8.tar.xz
+wrapdb_version = 1.1.8-1
+
+[provide]
+cmocka = cmocka_dep

test/rist/unit/meson.build

@@ -1,13 +1,17 @@
-cmocka = meson.get_compiler('c').find_library('cmocka', required: false)
+cmocka = dependency('cmocka', required: false, fallback: ['cmocka', 'cmocka_dep'])
 
 if cmocka.found()
 	if have_srp
+		srp_unit_deps = [threads, cmocka, crypto_deps]
+		if host_machine.system() == 'windows'
+			srp_unit_deps += cc.find_library('bcrypt')  # random.c calls BCryptGenRandom
+		endif
 		srp_unit = executable('srp_unit', rev_target,
 								'srp_examples.c',
 								'../../../contrib/pthread-shim.c',
 								'../../../src/crypto/random.c',
 								include_directories : inc,
-								dependencies : [threads, cmocka,crypto_deps],
+								dependencies : srp_unit_deps,
 		)
 
 		test('srp_unit_test', srp_unit, suite:['unit'])